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Basic R Programming MCQ

1. Point out the correct statement.

Empty vectors can be created with the vector() function

A sequence is represented as a vector but can contain objects of different classes

“raw” objects are commonly used directly in data analysis

None of the mentioned

Answer

Correct Answer: Empty vectors can be created with the vector() function

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2.
What can a factor hold?

Strings

Integers

Both strings and integers

None of the mentioned

Answer

Correct Answer: Both strings and integers

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3.
Identify which of the following expressions will give an error in R:

_abc <- 1

"a + b" <- 1

" " <- 1

":)" <- 1

Answer

Correct Answer: _abc <- 1

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4.
Which of the following is an invalid assignment ?

> x <- list("Los Angeles" = 1, Boston = 2, London = 3)

> names(x) <- c("New York", "Seattle", "Los Angeles")

> name(x) <- c("New York", "Seattle", "Los Angeles")

None of the mentioned

Answer

Correct Answer: > name(x) <- c("New York", "Seattle", "Los Angeles")

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5.
____ loops over a list and evaluate a function on each element.

apply()

lapply()

sapply()

mapply()

Answer

Correct Answer: apply()

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6.
Which of the following is a valid body of split function ?

function (x, f)

function (x, drop = FALSE, …)

function (x, f, drop = FALSE, …)

All of the mentioned

Answer

Correct Answer: function (x, f, drop = FALSE, …)

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7.
Lst <- list(name="Fred", wife="Mary", no.children=3, child.ages=c(4,7,9)) What is the value of length(Lst)?

Answer

Correct Answer: 4

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8.
What is the use of the doBY package?

defines the desired table using function and model formula

defines the desired view using function and model formula

defines the desired controller using function and model formula

defines the desired data using function and class formula

Answer

Correct Answer: defines the desired table using function and model formula

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9.
Which statement changes the column name to h and f of a matrix m?

colnames(m) <- c("h", "f")

columnnames(m) <- c("h", "f")

rownames(m) <- c("h", "f")

None of the mentioned

Answer

Correct Answer: colnames(m) <- c("h", "f")

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10.
What is the difference between seq(4) and seq_along(4)?

seq(4) produces a vector from 1 to 4 (c(1, 2, 3, 4)), and seq_along(4) produces a vector of length(4), or 1 (c(1))

seq(4) produces a vector from 1 to 3 (c(0, 1, 2, 3)), and seq_along(4) produces a vector of length(4), or 0 (c(0))

seq(4) produces a vector from 0 to 4 (c(1, 2, 3, 4)), and seq_along(4) produces a vector of length(4), or 1 (c(1))

None of the above

Answer

Correct Answer: seq(4) produces a vector from 1 to 4 (c(1, 2, 3, 4)), and seq_along(4) produces a vector of length(4), or 1 (c(1))

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11.
Which package in R supports the exploratory analysis of genomic data?

ecomic

adegenet

expoerety

adegen

Answer

Correct Answer: adegenet

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12.
What is the result of the following R code? > x <- 0:6 > y <- x[2 * 1:3] > length(y) <- 2 > y

[1] 0 1 2 3 4 5 6

[1] 0 2 4 6 2 2 2

[1] 2 4 6 2 4 6 2

[1] 0 1

[1] 1 3

[1] 0 3

[1] 2 1

Answer

Correct Answer: [1] 1 3

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13.
What is the output of the following expression? > c(0, FALSE)

[1] 0 FALSE

[1] "0" "FALSE"

[1] 0 "FALSE"

[1] "0" FALSE

[1] "0" "0"

[1] 0 "0"

[1] "0" 0

[1] 0 0

Answer

Correct Answer: [1] 0 0

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14.
What is the result of the following code? > x <- 0:3 > y <- as.character(x) > z <- as.integer(y) > z

[1] 0 3

[1] '3' '2' '1' '0'

[1] 3 2 1 0

[1] 1 2 3

[1] 0 1 2 3

[1] '0' '1' '2' '3'

[1] "0" "1" "2" "3"

Answer

Correct Answer: [1] 0 1 2 3

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15.
What is the output of the following commands? > x <- paste(c("X", "Y"), 1:2, sep='') > x

[1] "X" "Y" "X" "Y"

[1] "X1" "Y1" "X2" "Y2"

[1] "X1" "Y2" "X1" "Y2"

[1] "X1" "Y2"

[1] "X" "Y"

[1] "X1" "X2" "Y1" "Y2"

Answer

Correct Answer: [1] "X1" "Y2"

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16.
In an R list, '[[...]]' is ......

a general sub scripting operator.

the operator used to select a single element.

the assignment operator.

None of the above

Answer

Correct Answer: the operator used to select a single element.

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17.
What are the different types of sorting algorithms available in R?

Bucket

Selection

Bubble

Merge

All of the above

Answer

Correct Answer: All of the above

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18.
_____ function removes predictors that are sparse and highly unbalanced?

nearZeroVar

findCorrelation

filterVarImp

predictors

Answer

Correct Answer: nearZeroVar

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19.
What is returned by the following code? x <- 0 y <- 10 f <- function() { x <- 1 g() } g <- function() { x <- 2 h() } h <- function() { x <- 3 x + y } f()

[1] 0

[1] 2

[1] 3

[1] 10

[1] 11

[1] 12

[1] 13

[1] 15

Answer

Correct Answer: [1] 13

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20.
Does the following expression throw an error? f2 <- function(a, b) { a * 10 } f2(10, stop("This is not an error!"))

Yes

It depends.

Sometimes.

Answer

Correct Answer: No

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21.
Which of the expressions below result in the following output?
> [1] "a b"

> `%/\\%` <- function(a, b){ return(paste(a, b))} > "a" %/\% " b"

> `%-%` <- function(a, b){ return(paste(a, b))} > `%-%`("a", " b")

> a + b

> "a" + " b"

Answer

Correct Answer:

> `%/\\%` <- function(a, b){ return(paste(a, b))} > "a" %/\% " b"

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22.
What is the output of the following code? > y <- 5; f <- function(x) { y <-2; y^2 + g(x)}; g <- function(x) { x + y } > f(4)

Answer

Correct Answer: 13

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23.
Point out the wrong statement.

A formal argument can be a symbol, a statement of the form ‘symbol = expression’, or the special formal argument

The first component of the function declaration is the keyword function

The value returned by the call to function is not a function

None of the mentioned

Answer

Correct Answer: A formal argument can be a symbol, a statement of the form ‘symbol = expression’, or the special formal argument

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24.
What will be the output of the following code ? > f <- function() { + ## This is an empty function + } > f()

No result

NULL

All of the above

Answer

Correct Answer: NULL

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25.
M2 performs class prediction based on ___ data and clinical parameters?

microarray

MAclinical

CRAN

Answer

Correct Answer: microarray

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26.
Data frames in R language can be merged manually using? Check all that apply.

cbind ()

merge ()

bind()

loglm()

Answer

Correct Answer: cbind ()
merge ()

Note: This question has more than 1 correct answers

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27.
What would be the output of the following code ? > x <- 1:4 > x > 2

1 2 3 4

FALSE FALSE TRUE TRUE

1 2 3 4 5

All of the mentioned

Answer

Correct Answer: FALSE FALSE TRUE TRUE

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28.
fun1 <- function(a, b, c, ... ) { ans <- 2; ans} s <- fun1(1, 2, 3, 4, 5, 6, 7, 8) What is the value contained by s?

Answer

Correct Answer: 2
3
7

Note: This question has more than 1 correct answers

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29.
What is the output of the following commands? > x <- c(1, 2) > y <- c(x, 0, x) > z <- 2*x + y + 1 > z

[1] Inf

[1] 4 7

[1] 4 7 3 5 6

[1] 4 7 3 0 0

[1] 4 7 3 4 7

Error

Answer

Correct Answer: Error

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30.
What does the following code return? x <- 5 f1 <- function(x) { function() { x + 6 } } f1(3)()

Answer

Correct Answer: 9

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31.
fun1 <- function(data, data.frame, graph=TRUE, limit=20) { ... [ function body omitted] ... } Which of the following does NOT involve a valid invocation of this function?

ans <- fun1(d)

ans <- fun1(d, df)

and <- fun1(d, df, limit=10)

None of the above

Answer

Correct Answer: ans <- fun1(d)

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32.
Which code can be used for converting all variables?

col_names <- names(mydata) mydata[,col_names] <- lapply(mydata[,col_names] , factor)

names <- c('Freezk' ,'Mahnosr') mydata[,names] <- lapply(mydata[,names] , factor) str(mydata)

mydata[sapply(mydata, is.numeric)] <- lapply(mydata[sapply(mydata, is.numeric)], as.factor)

col_names <- names(mydata) mydata[,col_names] <- lapply(mydata[,col_names] , factor)

Answer

Correct Answer: col_names <- names(mydata) mydata[,col_names] <- lapply(mydata[,col_names] , factor)
col_names <- names(mydata) mydata[,col_names] <- lapply(mydata[,col_names] , factor)

Note: This question has more than 1 correct answers

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33.
What is the output of the following commands?

> x <- c(1, 2)

> y <- c(x, 0, x)

> prod(y)

[1] 0

[1] 5

[1] 6

[1] 1 2 0 1 2

Answer

Correct Answer: [1] 1 2 0 1 2

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34.
What is the output of the following commands? > x <- c(-1, 0, 1, 2, NA) > (x+1)[(!is.na(x)) & x>0]

[1] -1 0 1 2 NA

[1] 0 1 2 3 NA

[1] 0 1 2 3

[1] 1 2 3

[1] 0 1 2 3 NA+1

[1] 2 3

Answer

Correct Answer: [1] 2 3

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35.
What are the column names of the dataset?

names(dataset)

colnames(dataset)

row.names(dataset)

rownames(dataset)

Answer

Correct Answer: names(dataset)
colnames(dataset)

Note: This question has more than 1 correct answers

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36.
"%UpWork%" <- function(x, y) {upw <- x + y; upw} ans <- c(1,2)%UpWork%c(2,3) What is value of ans?

(1, 2, 2, 3)

(2, 3)

(-1, -1)

(3, 5)

Answer

Correct Answer: (3, 5)

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37.
Which function performs classical multidimensional scaling?

cmdscale() function

cmscale() function

cmmultiscale() function

multiscale() function

Answer

Correct Answer: cmdscale() function

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38.
You can check to see whether an R object is NULL with the _____ function.

is.null()

is.nullobj()

null()

All of the mentioned

Answer

Correct Answer: is.null()

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39.
What is the output of the following expression? num <- 5; res <- 1; for (i in 1:num) { if (i%%2 == 0) {res <- res * i}}; res

120

Answer

Correct Answer: 8

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40.
__ prints out the function call stack after an error occurs?

print()

output()

trace()

traceback()

Answer

Correct Answer: traceback()

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41.
What is the output of the following expression? > x <- c(0, 1, 2, 3, 4, 5, 6, 7, 8, 9) > x[-(1:3)]

[1] 9 8 7

[1] 0 1 2

[1] 0 3 7

[1] 3 4 5 6 7 8 9

[1] 0 1 2 3 4 5 6

Answer

Correct Answer: [1] 3 4 5 6 7 8 9

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42.
Which code will rename the field old_name to new_name in the data frame called data?

colnames(data)[colnames(data)=="old_name"] <<- "new_name"

colnames(data)[colnames(data)=="old_name"] <- "new_name"

colnames(data)[colnames(data)=="old_name"] >- "new_name"

colnames(data)[colnames(data)="old_name"] <- "new_name"

Answer

Correct Answer: colnames(data)[colnames(data)=="old_name"] <- "new_name"

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43.
What would the following code print ? > x <- data.frame(foo = 1:4, bar = c(T, T, F, F)) > ncol(x)

Answer

Correct Answer: 2

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44.
In which of the following is HousePrice a data frame? (1) HousePrice <- data.frame(home=statef, postCode=zip, price=fee) (2) HousePrice <- read.table("house.data") (3) HousePrice <- scan("house.data", list("", 0, 0)

1 and 2

2 and 3

1, 2 and 3

Answer

Correct Answer: 1 and 2

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45.
___ function returns a vector of the same size as x with the elements arranged in increasing order.

sort()

orderasc()

orderby()

None of the mentioned

Answer

Correct Answer: orderasc()

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46.
Consider the following code output? x = "I love R Programming" library(stringr) str_to_title(x)

I love r programming

I LOVE R PROGRAMMING

I Love R Programming

I love R Programming

Answer

Correct Answer: I LOVE R PROGRAMMING

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47.
Which function is used to generate factor levels?

gen_levels()

gl()

gen_fact_levels()

factor_levels()

Answer

Correct Answer: gl()

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48.
___regression is used to predict the binary outcome from the given set of continuous predictor variables?

Homogeneity

Logistic

Parametric

Multivariate

Answer

Correct Answer: Logistic

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49.
How can you merge two data frames in R?

using cbind () functions

using the merge () function on common rows or columns

Using combine() function

Both 1 and 2

Answer

Correct Answer: Using combine() function

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50.
What are the row names of the data frame?

names(dataset)

colnames(dataset)

row.names(dataset)

rownames(dataset)

Answer

Correct Answer: row.names(dataset)
rownames(dataset)

Note: This question has more than 1 correct answers

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51.
Which statement makes a mosaic plot ?

histogram()

mosaicplot()

bar()

All of the mentioned

Answer

Correct Answer: mosaicplot()

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52.
What is the factor variable in R language?

Factor variables are categorical variables that hold either string or numeric values

Factor variables are used in various types of graphics and particularly for statistical modelling

Both 1 and 2

Factor variables are used in data types and classes

Answer

Correct Answer: Both 1 and 2

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53.
How do you create log linear models in R language?

loglm () function

trace() function

print() function

logim() function

Answer

Correct Answer: loglm () function

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54.
R is easily extensible through functions and ____?

Extensions

Classes

Methods

Librarys

Answer

Correct Answer: Extensions

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55.
What is the difference between matrix and dataframe?

Dataframe can contain only similar type of data but matrix can contain different types of data.

Dataframe can contain different types of data but matrix can contain only similar type of data.

Dataframe and matrix are the same.

None of the mentioned.

Answer

Correct Answer: Dataframe can contain different types of data but matrix can contain only similar type of data.

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56.
Which of the following determines the least-squares regression line ?

histo()

barlm()

All of the mentioned

Answer

Correct Answer: lm

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57.
Let v be a vector. What is the correct way of creating a factor from v?

factor(v)

create_factor(v)

v.factor()

v.create_factor()

Answer

Correct Answer: factor(v)

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58.
What is the result of the following R code? > x <- c(0, 1, 2, 3, 4, 5, 6, 7) > dim(x) <- c(2,2,2) > x[,2,]

[,1] [,2] [1,] 0 4 [2,] 2 6

[,1] [,2] [1,] 1 5 [2,] 3 7

[,1] [,2] [1,] 0 4 [2,] 1 5

[,1] [,2] [1,] 0 2 [2,] 1 3

[,1] [,2] [1,] 2 6 [2,] 3 7

[,1] [,2] [1,] 4 6 [2,] 5 7

Answer

Correct Answer: [,1] [,2] [1,] 2 6 [2,] 3 7

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59.
What is the result of the following code? > a <- array(c(0:1, 1:0), dim=c(2,2)) > a %*% a

[1] 1

[,1] [1,] 1

[,1] [,2] [1,] 0 1 [2,] 1 0

[,1] [,2] [1,] 1 0 [2,] 0 1

[1] 2

[1] 10

[,1] [,2] [1,] 0 0 [2,] 0 0

[,1] [,2] [1,] 1 1 [2,] 1 1

Answer

Correct Answer: [,1] [,2] [1,] 1 0 [2,] 0 1

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60.
What is the result of the following R code? > x <- array(0:7, dim=c(2,4)) > i <- array(c(1:2, 4:3), dim=c(2,2)) > x[i]

[1] 0 3

[1] 4 3

[1] 1 3

[1] 1 7

[1] 3 4

[1] 4 4

[1] 6 5

Answer

Correct Answer: [1] 6 5

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61.
How can you create scatterplot matrices?

pairs()

splom()

plot()

Both 1 and 2

Answer

Correct Answer: Both 1 and 2

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62.
Data frames can be converted to a matrix by calling data.__

matr()

mat()

matrix()

matrix

Answer

Correct Answer: matrix()

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63.
What is the result of the following R code? > x <- array(0:7, dim=c(2,2,2)) > i <- array(c(1:2, 4:3), dim=c(2,2)) > x[i]

[1] 0 1 2 3

[1] 0 1 3 2

[1] 0 4 2 6

[1] 0 2 4 6

[1] 1 5 7 3

[1] 7 5 3 1

Answer

Correct Answer: [1] 0 1 3 2

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64.
How do you obtain the transpose of a matrix m in R?

t(m)

transpose(m)

m.t()

m.transpose()

Answer

Correct Answer: t(m)

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65.
What is the output of the following code? > x <- c(0, 1, 2, 3, 4, 5, 6, 7) > dim(x) <- c(2,2,2) > x[1,1,2]

[1] 0

[1] 1

[1] 2

[1] 3

[1] 4

[1] 5

[1] 6

[1] 7

Answer

Correct Answer: [1] 4

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66.
Which of the following is lattice command for producing boxplots ?

plot()

bwplot()

xyplot()

All of the mentioned

Answer

Correct Answer: bwplot()

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67.
Point out the correct statement.

The elements of a logical vector cannot have the values TRUE, FALSE, and NA

Matrices are vectors with a dimension attribute

Numerical vectors are generated by conditions

All of the mentioned

Answer

Correct Answer: Matrices are vectors with a dimension attribute

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68.
Error is an indication that a fatal problem has occurred and __ of the function stops?

message

execution

warning

fatal

Answer

Correct Answer: execution

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69.
What is the output of the following code? > x <- outer(1:2, 1:2, FUN = "*") > x

[1] 1

[1] 2

[1] 4

[,1] [,2] [1,] 1 2 [2,] 2 1

[,1] [,2] [1,] 1 2 [2,] 2 4

[,1] [,2] [1,] 1 4 [2,] 4 1

Answer

Correct Answer: [,1] [,2] [1,] 1 2 [2,] 2 4

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70.
What is the result of the following R code? > a <- array(0:7, dim=c(2,2,2)) > b<-a%*%a > b[1]

140

Answer

Correct Answer: 140

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71.
While creating a data frame, the variables must have __ length?

Same

Different

does not matter

None

Answer

Correct Answer: Same

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72.
uniPlot uniforms and customizes plots of packages _ , __ and lattice?

uniCox, graphics

ggplot2, graphics

uniPlot, ggplot2

graphics, uniPlot

Answer

Correct Answer: ggplot2, graphics

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73.
What would be the output of the following code ? > m <- matrix(1:4, nrow = 2, ncol = 2) > dimnames(m) <- list(c("a", "b"), c("c", "d")) > m

c d a 1 3 b 2 4

c d a 1 2 b 2 3

c d a 1 3 b 4 2

All of the mentioned

Answer

Correct Answer: c d a 1 3 b 2 4

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74.
The following vector represents the country of each of 10 freelancers on UpWork: > country <- c("UK", "Vietnam", "USA", "Russia", "Russia", "Egypt", "UK", "Vietnam", "Egypt", "USA") The following vector represents the hourly rate of the same 10 freelancers: > hourlyRate <- c(10, 20, 30, 40, 50, 50 ,40 ,30 ,20 ,10) Which R command will show the average rate for each country?

hourlyRate/length(country)

mean(hourlyRate)/length(country)

tapply(mean, hourlyRate, country)

tapply(hourlyRate, country, mean)

mean(hourlyRate/length(country))

Answer

Correct Answer: tapply(hourlyRate, country, mean)

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75.
What is the output of the following expression? > c(list(1), "1")

[1] [[1]] "1"

[1] 1 1

[1] 1 "1"

[[1]] [1] 1 [[2]] [1] "1"

[[1]] [1] 1 [[2]] [1] 1

[,1] [,2] [1,] 1 1

[,1] [,2] [1,] 1 "1"

Answer

Correct Answer: [[1]] [1] 1 [[2]] [1] "1"

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76.
What is the output of the following commands? > x <- c(0, 1, 2) > y <- x != 0 > y

[1] TRUE

[1] FALSE

[1] FALSE FALSE FALSE

[1] FALSE TRUE TRUE

[1] TRUE FALSE FALSE

Answer

Correct Answer: [1] FALSE TRUE TRUE

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77.
What is the output of the following commands? > x <- c(1, 2) > y <- c(4, 5) > pmax(x, y)

[1] 2

[1] 5

[1] 2 5

[1] 4 5

[1] 1 5

Answer

Correct Answer: [1] 4 5

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78.
What is the output of the following commands? > x <- c(1, 2) > y <- c(4, 5) > pmax(x, y)

[1] 1 2 3 4 5 6 7 8 9

[1] 0 1 2 3 4 5 6 7 8 9

[1] 1 2 3 4 5 6 7 8 9 10

[1] 0 1 2 3 4 5 6 7 8 9 10

[1] -1 0 1 2 3 4 5 6 7 8

Answer

Correct Answer: [1] 0 1 2 3 4 5 6 7 8 9

Note: This Question is unanswered, help us to find answer for this one

79.
The ____ function takes an arbitrary number of arguments and concatenates them one by one into character strings?

copy()

multiscale()

bind()

traceback()

Answer

Correct Answer: copy()

Note: This Question is unanswered, help us to find answer for this one

80.
Functions are defined using the _____ directive and are stored as R objects.

function()

funct()

functions()

All of the mentioned

Answer

Correct Answer: function()

Note: This Question is unanswered, help us to find answer for this one

81.
Which function gives the structure of a data frame “df”?

describe(df)

str(df)

df.structure()

summary(df)

Answer

Correct Answer: str(df)

Note: This Question is unanswered, help us to find answer for this one

82.
What is the output of the following command? > 2*1:10

[1] 2 3 4 5 6 7 8 9 10

[1] 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

[1] 2 4 6 8 10 12 14 16 18 20

[1] 2 4 6 8 10

[1] 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10

Answer

Correct Answer: [1] 2 4 6 8 10 12 14 16 18 20

Note: This Question is unanswered, help us to find answer for this one

83.
Which of the following is lattice command for producing a scatterplot ?

plot()

lm()

xyplot()

All of the mentioned

Answer

Correct Answer: xyplot()

Note: This Question is unanswered, help us to find answer for this one

84.
Point out the correct statement.

split() takes elements of the list and passes them as the first argument of the function you are applying

You can use tsplit() to evaluate a function single time each with a same argument

Sequence of operations is sometimes referred to as “map-reduce”

None of the mentioned

Answer

Correct Answer: Sequence of operations is sometimes referred to as “map-reduce”

Note: This Question is unanswered, help us to find answer for this one

85.
What is the correct way of converting a factor to integer in R?

x <- factor(c(0, 4, 3, 3, 4)) str(x)

x1 = as.numeric(x) str(x1)

a2 = as.numeric(as.character(a)) str(a2)

a2 = as.numeric(as.factor(a)) str(a2)

Answer

Correct Answer: a2 = as.numeric(as.character(a)) str(a2)

Note: This Question is unanswered, help us to find answer for this one

86.
What is the output of the following commands? > x <- c(1:3, NA) > y <- is.na(x) > y

[1] TRUE

[1] FALSE

[1] FALSE TRUE

[1] FALSE FALSE

[1] TRUE TRUE TRUE TRUE

[1] FALSE FALSE FALSE FALSE

[1] FALSE FALSE FALSE TRUE

Answer

Correct Answer: [1] FALSE FALSE FALSE TRUE

Note: This Question is unanswered, help us to find answer for this one

87.
Point out the correct statement.

lapply() takes elements of the list and passes them as the first argument of the function you are applying

You can use lapply() to evaluate a function multiple times each with a different argument

Functions that you pass to lapply() may have other arguments

None of the mentioned

Answer

Correct Answer: None of the mentioned

Note: This Question is unanswered, help us to find answer for this one

88.
Melt is used to convert wide data to _____ data?

long

dcast

variable

infr

Answer

Correct Answer: long

Note: This Question is unanswered, help us to find answer for this one

89.
gzfile opens a connection to a file compressed with _____?

url

gzip

bzfile

gdata

Answer

Correct Answer: gzip

Note: This Question is unanswered, help us to find answer for this one

90.
Which function is used to convert a list ‘a’ to a vector?

a.as_vector()

unlist(a)

a.vector()

vector(a)

Answer

Correct Answer: unlist(a)

Note: This Question is unanswered, help us to find answer for this one

91.
What would be the output of the following code ? > x <- 1:3 > names(x)

NULL

None of the mentioned

Answer

Correct Answer: NULL

Note: This Question is unanswered, help us to find answer for this one

92.
Using the __ the BY variable should be in the list?

aggregate() function

aggregated() function

aggregates() function

aggregateted() function

Answer

Correct Answer: aggregate() function

Note: This Question is unanswered, help us to find answer for this one

93.
Lst <- list(name="Fred", wife="Mary", no.children=3, child.ages=c(4,7,9)) What is the value of Lst[[4]][2]?

Mary

(4, 7, 9)

Answer

Correct Answer: 7

Note: This Question is unanswered, help us to find answer for this one

94.
Lst <- list(name="Fred", wife="Mary", no.children=3, child.ages=c(4,7,9)) What is Lst[[1]]?

Fred

Mary

c(4, 7, 9)

Answer

Correct Answer: Fred

Note: This Question is unanswered, help us to find answer for this one

95. Which of the following commands is used to load the "xlsx" package into the R workspace?

install.packages('xlsx')

any(grepl('xlsx'.installed.packages()))

read.xlsx()

library('xlsx')

Answer

Correct Answer: library('xlsx')

Note: This Question is unanswered, help us to find answer for this one

96. Which of the following options is used for checking the directory to which the R workspace is pointing?

dir

getwd

user.dir

getcwd

Answer

Correct Answer: getwd

Note: This Question is unanswered, help us to find answer for this one

97. Which of the following control structures is used to execute an infinite loop?

for

while

repeat

Answer

Correct Answer: repeat

Note: This Question is unanswered, help us to find answer for this one

98. In R programming language. which of the following are the loop control statements?

repeat

while

for

break

Answer

Correct Answer: break
next

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

99.
What will be the output of the following program on R interpreter?
tempString <- "Hello.World!"
print (tempString)
tempString

[1] "Hello,World!"

[1] "Hello.World!"

Compilation error

Empty output

Answer

Correct Answer:

[1] "Hello,World!"

Note: This Question is unanswered, help us to find answer for this one

100.
What will be the output of the following program on R interpreter?
foo <- 'red'
switch(foo, fruit = "apple", vegetable = “chilli‘. "Exception')

red

apple

chilli

Exception

Answer

Correct Answer:

Exception

Note: This Question is unanswered, help us to find answer for this one

101.
What will be the output of the following program on R interpreter?
custom_cub_function <- function()
i
for(i in 1:4)
{
i
cubeoutput <- i"3
print[cubeoutput)
}

[1]1

[1]8

[1]27

[1]64

[1]3

[1]6

[1]9

[1]12

[1]0.3333333

[1] 0.6666667

[1]1

[1]1.333333

No output.

Answer

Correct Answer:

No output.

Note: This Question is unanswered, help us to find answer for this one

102. To create a relationship model, the lrn() function is used in R. Which of the following are the valid parameters for this function?

formula, which is a symbol. presenting the relation between x and y.

data. which is the vector on which the formula will be applied.

object, which is the formula that is already created using the lm0 function.

newdata, which is the vector containing the new value for the predictor variable.

Answer

Correct Answer: formula, which is a symbol. presenting the relation between x and y.
data. which is the vector on which the formula will be applied.

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

103. In R programming language, the library(x) function:

will load specif‌ied data sets.

will load add-on packages

will load the datasets written with save.

will start the HTML version of help.

Answer

Correct Answer: will load add-on packages

Note: This Question is unanswered, help us to find answer for this one

104.
You have an Excel workbook with the name "data.xlsx". it has 3 sheets. Which of the following options will load the Excel workbook and read the second sheet?

data <- readodsxrdataxlsx', sheetlndex =1)

data <~ read.xlsx(‘data.xlsx', sheetlndex = 2)

data <- read.xlsxt(data.xlsx'. sheetlndex = 3)

data <- read.xlsx('data.xlsx', sheetlndex = 0)

Answer

Correct Answer:

data <~ read.xlsx(‘data.xlsx', sheetlndex = 2)

Note: This Question is unanswered, help us to find answer for this one

105. In R programming. which of the following are the valid values for the data type, Numeric?

123L

1 1 123

999L

2 999

Answer

Correct Answer: 1 1 123
2 999

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

106.
R has four in-built functions to generate a normal distribution. Which of the following functions gives the height of the probability distribution at each point for a given mean and standard deviation?

dnorm(x, mean, sd)

pnorm(x, mean, sd)

qnorm(p, mean, sd)

rnorm(n, mean, sd)

Answer

Correct Answer:

dnorm(x, mean, sd)

Note: This Question is unanswered, help us to find answer for this one

107. In R programming. which of the following functions are included in the standard Strings Library?

grep(pattern.x)

match(x,table)

merge(a,b)

choose(n, k)

Answer

Correct Answer: grep(pattern.x)
match(x,table)

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

108.
in R language, in order to calculate the mean of a given set of values, the mean() function is used. Following is the basic syntax for the same:
mean(x, trim = O, na.rm = FALSE, ...)
Which of the following parameters is used to remove the missing values from the input vector?

trim

na.rm

Answer

Correct Answer:

na.rm

Note: This Question is unanswered, help us to find answer for this one

109.
R has four in-built functlons to generate a normal distributlon. Which of the following functions takes the probability value and gives a number. whose cumulative value matches the probability value?

dnorm(x.mean. sd)

pnorm(x.mean. sd)

qnorm(p.mean. sd)

rnorm(n. mean, sd)

Answer

Correct Answer:

qnorm(p.mean. sd)

Note: This Question is unanswered, help us to find answer for this one

110.
The middle-most value in a data series is called the median. The median() function is used. in R. to calculate this value. Which of the following are the valid parameters in the median() function?

x, which is the input vector.

trlm, which Is used to drop values from both ends of the sorted vector.

na.rm, which is used to remove the missing values from the input vector.

Answer

Correct Answer:

x, which is the input vector.

na.rm, which is used to remove the missing values from the input vector.

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

111.
What will be the output of the following R code?
car_colors <~ ci‘black',‘red','blue'.'blue'.'-.vltite'.‘metallic',‘red')
tactor_cars <~ Iactor(car_colors)
Print (factor_cars)
print(nlevels(factot_cats))

Levels: black blue metallic red white

[1]5

[1] black red blue blue White metallic red

Levels: black blue metallic red white

[1] 5

[l] 5

[1] black red blue blue white metallic red

Levels: black blue metallic red white

Answer

Correct Answer:

[1] black red blue blue White metallic red

Levels: black blue metallic red white

[1] 5

Note: This Question is unanswered, help us to find answer for this one

112.
What will be the output ofthe following program on R interpreter?
foo <- C("Testing","loop")
count <— 5
repeat {

print(foo)

count <- count +1

if(count > 8.34)[

break
}
]

[1]"Testing""loop"

[1] "Testing""loop"

[1]"Testing""loop"

[1] "Testing"“loop"

No output.

Answer

Correct Answer:

[1]"Testing""loop"

[1] "Testing""loop"

Note: This Question is unanswered, help us to find answer for this one

113.
What will be the output of the following program on R Interpreter?
foo <- c(‘Testing‘.’while statement‘)
cnt <- 7
while [cnt<11.64)
[
printltoo)
cnt = count + 1
]

No output.

[1] 'Testlng’”while statement’

[1] "Testing‘'while statement'

[1] “Testing“while statement‘

[1] "Testing"‘while statement'

[1] "Testing”while statement‘

[1] 'Testing"'while statement'

[1] "Testing-while statement‘

[1] "Testing‘"‘while statement‘

Error in code executlon

Answer

Correct Answer:

[1] 'Testlng’”while statement’

[1] "Testing‘'while statement'

[1] “Testing“while statement‘

[1] "Testing"‘while statement'

[1] "Testing”while statement‘

Note: This Question is unanswered, help us to find answer for this one

114.
Following is a function def‌inition in R programming language:
foo.function <- function(a =1, b = 2. c = 3)
{result <- a ’ b+ c
print(result)
}

foo.functlon()

foo.functlon(8,6,4)

foo.functlon(b=10,a=9)

foo.function(1;1,1,1)

Answer

Correct Answer:

foo.functlon()

foo.functlon(8,6,4)

foo.functlon(b=10,a=9)

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

115. Which of the following statements is/are correct?

print(rootnode[[1]]11]]) will get the f‌irst element of the second node

printfrootnodef‌limm) will get the f‌irst element of the f‌irst node.

xmlToDataFrarnefinputxml

xmlSize(rootnode) will f‌ind the number of child nodes under the root node.

Answer

Correct Answer: print(rootnode[[1]]11]]) will get the f‌irst element of the second node
printfrootnodef‌limm) will get the f‌irst element of the f‌irst node.
xmlToDataFrarnefinputxml
xmlSize(rootnode) will f‌ind the number of child nodes under the root node.

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

116.
Following is a code snippet executed on R interpreter:
sales <- c(10,20.30.40.50)
months <- c{"JAN".“FEB"."MARCH"."APRIL"."MAY")
png(file = "months_sales.png")
barplot(sales,names.arg = months.xlab = "Month".ylab = "Sales",col = "Red",main = "Sales Chart“,border =
"Black")
What does this code do?

It creates the vector data for the bar chart.

It gives a name to the chart f‌ile.

It plots the bar chart.

It saves the chart as per the mentioned f‌ile name.

Answer

Correct Answer:

It creates the vector data for the bar chart.

It gives a name to the chart f‌ile.

It plots the bar chart.

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

117.
Find the error in following code snippet
foodata <- data.frame(
empid = C(11:15),
empname = c("EMP2"."EMP3"."EMP4","EMP5"),
"" = c(100,200,300,400,500},
empjoindate = asDatetcf'2017—01-01", '2017~02~01", '2017-03-01‘, "2017-0401”,"2017~05-01‘)),
stringsAsFactors = FALSE
)
print(foo.data)

One of the column names has a zero-length variable name.

The column

The data stored in a data frame is not of character type.

The row names are not unique.

Answer

Correct Answer:

One of the column names has a zero-length variable name.

The column

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

118. Which of the following functions is used for variable conversions?

as.array

ls.data.frame

class(x)

whichmax(x)

Answer

Correct Answer: as.array

Note: This Question is unanswered, help us to find answer for this one

119.
What wlll be the Output of the following program on R Interpreter?
v <- LETTERS[5:1]
{or (i in v)
{
print(i)
}

[1] “E”

[1] "D"

[1] “C”

[1] "B"

[1] "A.”

[1] “A”

[1] 'B-.

[I] "C'

[1] “A"

[‘1 “B

[1] "C'

[1] D"

[1] "E'

No output.

Answer

Correct Answer:

[1] “E”

[1] "D"

[1] “C”

[1] "B"

[1] "A.”

Note: This Question is unanswered, help us to find answer for this one

120. Which of the following functions computes the combinations of k events among n repetitions = ner_(n-k)!kl]?

which(n = k)

match(n, k)

merge(n,k)

choose(n. K)

Answer

Correct Answer: choose(n. K)

Note: This Question is unanswered, help us to find answer for this one

121.
Following is a code snippet to be used to draw a boxplot in R:
boxplot(mpg "‘ Cyl, data = mtcars,
xiab = "Number of Cylinders",
ylab = Miles Per Gallon“,
main = "Mileage Data",
notch = TRUE,
varwldth = FALSE.
col = ched","Biue","Green"],
names = c("High","Medium","Low")
Which of the following options is NOT correct?

it will draw a boxplot with 'Number of Cylinders' values on x axis and the Miles Per Gallon' data on y axis.

it will give a title to the graph as Mileage Data

it will draw the notch graphs

It will draw a box with the width proportionate to the sample (data inputted) size.

it will fill the color of the boxes as red, blue and green, respectively.

Answer

Correct Answer:

It will draw a box with the width proportionate to the sample (data inputted) size.

Note: This Question is unanswered, help us to find answer for this one

122. In R programming. a pie chart is created using the plea function. Which of the following parameters is used to give description to the slices?

col

labels

radius

main

Answer

Correct Answer: labels

Note: This Question is unanswered, help us to find answer for this one

123. Which of the following commands is used to check and verify whether or not the ”xlsx" package is installed?

install.packages('xlsx‘)

any(grepl(‘x|sx',instalIed.packages()))

library('xlsx')

read.xlsx()

Answer

Correct Answer: any(grepl(‘x|sx',instalIed.packages()))

Note: This Question is unanswered, help us to find answer for this one

124. There is a csv f‌ile named "data.csv". Which of the following options will read that csv f‌ile in R programming?

output <- read.csv('data.csv')

output <- readcsv(‘'data.csv')

output <- read('data.csv')

output <- readf‌ile.csv('data.csv‘)

Answer

Correct Answer: output <- read.csv('data.csv')

Note: This Question is unanswered, help us to find answer for this one

125. Which of the following decision-making statements is used to test a variable for equality against a list of values?

If...else

while

Switch

Answer

Correct Answer: Switch

Note: This Question is unanswered, help us to find answer for this one

126. Which of the following are the valid vector Inputs to the pie() function?

foo <- c[O. 0.0.0)

foo <. c[10. 10. 10. 70)

foo <- c(-10. 10. 0. 90)

foo <- c[0. 10. 10. 90)

Answer

Correct Answer: foo <. c[10. 10. 10. 70)
foo <- c[0. 10. 10. 90)

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

127. In R programming language. which of the following statements is NOT correct about operators?

operator creates the series of numbers in sequence for a vector.

0%in% operator is used to multiply a matrix with its transpose.

%/% operator gives result of the division of f‌irst vector with second (quotient).

^ operator gives the remainder of the division of first vector with the second.

Answer

Correct Answer: operator creates the series of numbers in sequence for a vector.

Note: This Question is unanswered, help us to find answer for this one

128.
What will be the output of the following program on R interpreter?
temp <- c("Comp|ex","Simple")
cnt <- 10
repeat
[
print(temp)
cnt <— cnt-1
if(cnt < 6.5) {
break
1
}

[1]"Complex""Simple"

[1] "Complex""Simple"

Error in code execution

System timeout error.

[1]"Complex""Simple"

[1] "Complex""Simple"

Answer

Correct Answer:

[1]"Complex""Simple"

[1] "Complex""Simple"

Note: This Question is unanswered, help us to find answer for this one

129. Which of the following options represents an atomic vector of the numeric type?

print(24L)

print(24)

printr12.5)

print(2+3i)

Answer

Correct Answer: print(24)

Note: This Question is unanswered, help us to find answer for this one

130. in R programming. a pie chart is created using the piel] function. Which of the following parameters indicates the title of the chart?

col

labels

radius

main

Answer

Correct Answer: main

Note: This Question is unanswered, help us to find answer for this one

131.
Following Is a function def‌inition in R programming language:
foo.function <- function(a,b)
{
print{a)
print{b‘b)
}
Which of the following function calls will give an error?

foo.function

foo.functlon(9,5)

foo.function[b=2,4)

foo.functlon(9)

Answer

Correct Answer:

foo.functlon(9)

Note: This Question is unanswered, help us to find answer for this one

132.
What will be the output of the following program on R interpreter?
OUTPUTMATRIX = matrix( c("1","2"."3"."4"."5"."6"."7"."8"."9"."10"."11","12"). nrow = 4, ncol = 3. byrow = FALSE)
print(OUTPUTMATRlX)

[,1] [,2] [.3]

[1,] '1' '2' '3'

[2.] '4' '5' '6'

[3']'7' '8' '9'

[4.] '10' '11' '12'

[1].[2][.3][,4]

[1'] 1' '2' '3' '4'

[2’] '5' '6' '7' '8'

[3'] '9' '10' 11'12'

[111.211.311.41

[1,] '1' ' 4III7IIH10'

[2,] '2' '5ll118lll11'

[3’] '3' '6' '9' '12'

[.1] [.2] [.3]

[1.] '1' ' 5' '9'

[2.] '2' '6' '10'

[3.] '3' '7' '11'

[4.] '4' '8' '12'

Answer

Correct Answer:

[.1] [.2] [.3]

[1.] '1' ' 5' '9'

[2.] '2' '6' '10'

[3.] '3' '7' '11'

[4.] '4' '8' '12'

Note: This Question is unanswered, help us to find answer for this one

133. In R programming. which of the following are the valid values for the data type, Integer?

13 4L

Answer

Correct Answer: 13 4L
0L

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

134.
Following is a function definition in R programming language:

dummy.function <- function(a.b.c) [
result -=- a ‘+ b ' c
print(result)
]

Which of the following function calls will give the output: 41895?

dummy.function(1345.200.31)

dummy.function(200.1345.31)

dummy.function(1345.31.200)

dumnly.function(b=1345.a=200.c=31]

Answer

Correct Answer:

dummy.function(200.1345.31)

dumnly.function(b=1345.a=200.c=31]

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

135.
What will be the output of the following code on the R Interpreter?
print(seq(7,12. by = 0.68))

[1] 7.68 8.36 9.04 9.7210.4011.0811.76

[1] 7.00 7.68 8.36 9.04 9.7210.4011.0811.76

[1] 7.00 7.68 8.36 9.04 9.7210.4011.08

[1] 7.68 8.36 9.04 9.7210.4011.08

Answer

Correct Answer:

[1] 7.00 7.68 8.36 9.04 9.7210.4011.0811.76

Note: This Question is unanswered, help us to find answer for this one

136.
In R programming language. the arguments of a function can be partially matched using the following checks:
Check for a partial match.
Check for a positional match.
Check for exact match for a named argument
Which of the following Is the correct sequence of checks followed by the function to partially match the supplied arguments?

ABC

BCA

CAB

AcB

Answer

Correct Answer:

CAB

Note: This Question is unanswered, help us to find answer for this one

137. In R programming. in order to read a text file, the read.table() function is used. Which of the following options are the valid arguments for this function?

file

header

what

sep

quote

Answer

Correct Answer: file
header
sep
quote

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

138.
What will be the output of the following program on R Interpreter?
v <- 3+16i
printiclass()
v <— 3"46
print[class[v])

v <~ 3l+16
printiclassMJ

v <- 316

print(class[v))

O [t] 'complex'

[1119

[1] 'character'

[1] 'numeric‘

[[1] 'complex'

[1] 'numeric'

[1] 'complex'

[1] 'numeric'

Compilation error

Runtime error

Answer

Correct Answer:

[[1] 'complex'

[1] 'numeric'

[1] 'complex'

[1] 'numeric'

Note: This Question is unanswered, help us to find answer for this one

139. What will be the output of the following line of code on R Interpreter?

Empty output

TESTOUTPUT

Compilation error

[1] TESTOUTPUT

Answer

Correct Answer: [1] TESTOUTPUT

Note: This Question is unanswered, help us to find answer for this one

140.
What will be the output of the following program on R interpreter?
v <- LETTERS[9.55:15.86]
for ( i in v)
{
if (i = "0")(

next

]
print(i)
}

[1]'1'

[1] 'J'

[1]'k'

[1] 'L'

[1]M'

[1] 'N'

[1] '0'

[1] 'l'

[11 'J'

[1] 'K'

[1]'’L'

[1]'M'

[1]W

No output.

[1] 'G'

Answer

Correct Answer:

[1]'1'

[1] 'J'

[1]'k'

[1] 'L'

[1]M'

[1] 'N'

[1] '0'

Note: This Question is unanswered, help us to find answer for this one

141. Which of the following are related to slicing and extracting data by indexing lists?

Xl-(iznll

Xllnil

['1'] xf‌l'name

F1 x[i,j]

Answer

Correct Answer: Xllnil
['1'] xf‌l'name

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

142. Which of the following options represents an atomic vector of the integer type?

print(24L)

print(24)

print(12.5)

print(2+3i)

Answer

Correct Answer: print(2+3i)

Note: This Question is unanswered, help us to find answer for this one

143. In R programming language, the indexing vectors, xl-[lzn)]. will:

get the first n elements.

get elements from n+1 to the end.

get the nth element

get all elements but the nth element.

Answer

Correct Answer: get elements from n+1 to the end.

Note: This Question is unanswered, help us to find answer for this one

144.
Which of the given tasks are performed by the following code?
library("rjso")
result <- fromJSON(lile = '"data.json"]
print(result)

I It loads the package required to read JSON files.

It reads the file

It prints the contents of the [son file.

None of the above.

Answer

Correct Answer:

I It loads the package required to read JSON files.

It reads the file

It prints the contents of the [son file.

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

145.
R uses the function. barplotii. to create bar charts. The basic syntax to create a bar chart In R is:
barplot(H. xlab. yiab. main. namesarg. col)
Which of the following options are correct?

H is the title of the bar chart.

main is a vector or matrix containing numeric values used in the bar chart.

namesarg is a vector of names appearing under each bar.

col is used to give colors to the bars in the graph.

Answer

Correct Answer:

namesarg is a vector of names appearing under each bar.

col is used to give colors to the bars in the graph.

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

146. Which of the following functions is used to join multiple vectors to create a data frame?

cbind()

rbind()

merge()

meit()

Answer

Correct Answer: cbind()

Note: This Question is unanswered, help us to find answer for this one

147. Which of the following statements terminates the loop statement and transfers execution to the immediate statement?

for

break

Answer

Correct Answer: break

Note: This Question is unanswered, help us to find answer for this one

148.
Find the output of the following code on the R Interpreter.
months <- c{"JAN"."FEB"."MARCH"."APRIL"."MAY"."JUNE"."JULY")
output <- months[c(1.TRUE.4.TRUE.5)]
print(output)

[1]'JAN' 'JAN' 'APRIL' 'JAN' 'MAY'

[1]'JAN' 'FEB' 'APRIL' 'JAN' 'MAY'

[1]' JAN' 'JAN' 'APRIL' 'MAY' ‘JUNE'

[1]' JAN' 'FEB' 'MARCH' 'APRIL' 'MAY'

Answer

Correct Answer:

[1]'JAN' 'JAN' 'APRIL' 'JAN' 'MAY'

[1]' JAN' 'FEB' 'MARCH' 'APRIL' 'MAY'

Note: This question has more than 1 correct answers

Note: This Question is unanswered, help us to find answer for this one

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Basic R Programming MCQ

1. Point out the correct statement.

2. What can a factor hold?

3. Identify which of the following expressions will give an error in R:

4. Which of the following is an invalid assignment ?

5. ____ loops over a list and evaluate a function on each element.

6. Which of the following is a valid body of split function ?

7. Lst <- list(name="Fred", wife="Mary", no.children=3, child.ages=c(4,7,9)) What is the value of length(Lst)?

8. What is the use of the doBY package?

9. Which statement changes the column name to h and f of a matrix m?

10. What is the difference between seq(4) and seq_along(4)?

11. Which package in R supports the exploratory analysis of genomic data?

12. What is the result of the following R code? > x <- 0:6 > y <- x[2 * 1:3] > length(y) <- 2 > y

13. What is the output of the following expression? > c(0, FALSE)

14. What is the result of the following code? > x <- 0:3 > y <- as.character(x) > z <- as.integer(y) > z

15. What is the output of the following commands? > x <- paste(c("X", "Y"), 1:2, sep='') > x

16. In an R list, '[[...]]' is ......

17. What are the different types of sorting algorithms available in R?

18. _____ function removes predictors that are sparse and highly unbalanced?

19. What is returned by the following code? x <- 0 y <- 10 f <- function() { x <- 1 g() } g <- function() { x <- 2 h() } h <- function() { x <- 3 x + y } f()

20. Does the following expression throw an error? f2 <- function(a, b) { a * 10 } f2(10, stop("This is not an error!"))

21. Which of the expressions below result in the following output?> [1] "a b"

22. What is the output of the following code? > y <- 5; f <- function(x) { y <-2; y^2 + g(x)}; g <- function(x) { x + y } > f(4)

23. Point out the wrong statement.

24. What will be the output of the following code ? > f <- function() { + ## This is an empty function + } > f()

25. M2 performs class prediction based on ___ data and clinical parameters?

26. Data frames in R language can be merged manually using? Check all that apply.

27. What would be the output of the following code ? > x <- 1:4 > x > 2

28. fun1 <- function(a, b, c, ... ) { ans <- 2; ans} s <- fun1(1, 2, 3, 4, 5, 6, 7, 8) What is the value contained by s?

29. What is the output of the following commands? > x <- c(1, 2) > y <- c(x, 0, x) > z <- 2*x + y + 1 > z

30. What does the following code return? x <- 5 f1 <- function(x) { function() { x + 6 } } f1(3)()

31. fun1 <- function(data, data.frame, graph=TRUE, limit=20) { ... [ function body omitted] ... } Which of the following does NOT involve a valid invocation of this function?

32. Which code can be used for converting all variables?

33. What is the output of the following commands? > x <- c(1, 2) > y <- c(x, 0, x) > prod(y)

34. What is the output of the following commands? > x <- c(-1, 0, 1, 2, NA) > (x+1)[(!is.na(x)) & x>0]

35. What are the column names of the dataset?

36. "%UpWork%" <- function(x, y) {upw <- x + y; upw} ans <- c(1,2)%UpWork%c(2,3) What is value of ans?

37. Which function performs classical multidimensional scaling?

38. You can check to see whether an R object is NULL with the _____ function.

39. What is the output of the following expression? num <- 5; res <- 1; for (i in 1:num) { if (i%%2 == 0) {res <- res * i}}; res

40. __ prints out the function call stack after an error occurs?

41. What is the output of the following expression? > x <- c(0, 1, 2, 3, 4, 5, 6, 7, 8, 9) > x[-(1:3)]

42. Which code will rename the field old_name to new_name in the data frame called data?

43. What would the following code print ? > x <- data.frame(foo = 1:4, bar = c(T, T, F, F)) > ncol(x)

44. In which of the following is HousePrice a data frame? (1) HousePrice <- data.frame(home=statef, postCode=zip, price=fee) (2) HousePrice <- read.table("house.data") (3) HousePrice <- scan("house.data", list("", 0, 0)

45. ___ function returns a vector of the same size as x with the elements arranged in increasing order.

46. Consider the following code output? x = "I love R Programming" library(stringr) str_to_title(x)

47. Which function is used to generate factor levels?

48. ___regression is used to predict the binary outcome from the given set of continuous predictor variables?

49. How can you merge two data frames in R?

50. What are the row names of the data frame?

51. Which statement makes a mosaic plot ?

52. What is the factor variable in R language?

53. How do you create log linear models in R language?

54. R is easily extensible through functions and ____?

55. What is the difference between matrix and dataframe?

56. Which of the following determines the least-squares regression line ?

57. Let v be a vector. What is the correct way of creating a factor from v?

58. What is the result of the following R code? > x <- c(0, 1, 2, 3, 4, 5, 6, 7) > dim(x) <- c(2,2,2) > x[,2,]

59. What is the result of the following code? > a <- array(c(0:1, 1:0), dim=c(2,2)) > a %*% a

60. What is the result of the following R code? > x <- array(0:7, dim=c(2,4)) > i <- array(c(1:2, 4:3), dim=c(2,2)) > x[i]

61. How can you create scatterplot matrices?

62. Data frames can be converted to a matrix by calling data.__

63. What is the result of the following R code? > x <- array(0:7, dim=c(2,2,2)) > i <- array(c(1:2, 4:3), dim=c(2,2)) > x[i]

64. How do you obtain the transpose of a matrix m in R?

65. What is the output of the following code? > x <- c(0, 1, 2, 3, 4, 5, 6, 7) > dim(x) <- c(2,2,2) > x[1,1,2]

66. Which of the following is lattice command for producing boxplots ?

67. Point out the correct statement.

68. Error is an indication that a fatal problem has occurred and __ of the function stops?

69. What is the output of the following code? > x <- outer(1:2, 1:2, FUN = "*") > x

70. What is the result of the following R code? > a <- array(0:7, dim=c(2,2,2)) > b<-a%*%a > b[1]

71. While creating a data frame, the variables must have __ length?

72. uniPlot uniforms and customizes plots of packages _ , __ and lattice?

73. What would be the output of the following code ? > m <- matrix(1:4, nrow = 2, ncol = 2) > dimnames(m) <- list(c("a", "b"), c("c", "d")) > m

75. What is the output of the following expression? > c(list(1), "1")

76. What is the output of the following commands? > x <- c(0, 1, 2) > y <- x != 0 > y

77. What is the output of the following commands? > x <- c(1, 2) > y <- c(4, 5) > pmax(x, y)

78. What is the output of the following commands? > x <- c(1, 2) > y <- c(4, 5) > pmax(x, y)

79. The ____ function takes an arbitrary number of arguments and concatenates them one by one into character strings?

80. Functions are defined using the _____ directive and are stored as R objects.

2.
What can a factor hold?

3.
Identify which of the following expressions will give an error in R:

4.
Which of the following is an invalid assignment ?

5.
____ loops over a list and evaluate a function on each element.

6.
Which of the following is a valid body of split function ?

7.
Lst <- list(name="Fred", wife="Mary", no.children=3, child.ages=c(4,7,9)) What is the value of length(Lst)?

8.
What is the use of the doBY package?

9.
Which statement changes the column name to h and f of a matrix m?

10.
What is the difference between seq(4) and seq_along(4)?

11.
Which package in R supports the exploratory analysis of genomic data?

12.
What is the result of the following R code? > x <- 0:6 > y <- x[2 * 1:3] > length(y) <- 2 > y

13.
What is the output of the following expression? > c(0, FALSE)

14.
What is the result of the following code? > x <- 0:3 > y <- as.character(x) > z <- as.integer(y) > z

15.
What is the output of the following commands? > x <- paste(c("X", "Y"), 1:2, sep='') > x

16.
In an R list, '[[...]]' is ......

17.
What are the different types of sorting algorithms available in R?

18.
_____ function removes predictors that are sparse and highly unbalanced?

19.
What is returned by the following code? x <- 0 y <- 10 f <- function() { x <- 1 g() } g <- function() { x <- 2 h() } h <- function() { x <- 3 x + y } f()

20.
Does the following expression throw an error? f2 <- function(a, b) { a * 10 } f2(10, stop("This is not an error!"))

21.
Which of the expressions below result in the following output?
> [1] "a b"

22.
What is the output of the following code? > y <- 5; f <- function(x) { y <-2; y^2 + g(x)}; g <- function(x) { x + y } > f(4)

23.
Point out the wrong statement.

24.
What will be the output of the following code ? > f <- function() { + ## This is an empty function + } > f()

25.
M2 performs class prediction based on ___ data and clinical parameters?

26.
Data frames in R language can be merged manually using? Check all that apply.

27.
What would be the output of the following code ? > x <- 1:4 > x > 2

28.
fun1 <- function(a, b, c, ... ) { ans <- 2; ans} s <- fun1(1, 2, 3, 4, 5, 6, 7, 8) What is the value contained by s?

29.
What is the output of the following commands? > x <- c(1, 2) > y <- c(x, 0, x) > z <- 2*x + y + 1 > z

30.
What does the following code return? x <- 5 f1 <- function(x) { function() { x + 6 } } f1(3)()

31.
fun1 <- function(data, data.frame, graph=TRUE, limit=20) { ... [ function body omitted] ... } Which of the following does NOT involve a valid invocation of this function?

32.
Which code can be used for converting all variables?

33.
What is the output of the following commands?

> x <- c(1, 2)

> y <- c(x, 0, x)

> prod(y)

34.
What is the output of the following commands? > x <- c(-1, 0, 1, 2, NA) > (x+1)[(!is.na(x)) & x>0]

35.
What are the column names of the dataset?

36.
"%UpWork%" <- function(x, y) {upw <- x + y; upw} ans <- c(1,2)%UpWork%c(2,3) What is value of ans?

37.
Which function performs classical multidimensional scaling?

38.
You can check to see whether an R object is NULL with the _____ function.

39.
What is the output of the following expression? num <- 5; res <- 1; for (i in 1:num) { if (i%%2 == 0) {res <- res * i}}; res

40.
__ prints out the function call stack after an error occurs?

41.
What is the output of the following expression? > x <- c(0, 1, 2, 3, 4, 5, 6, 7, 8, 9) > x[-(1:3)]

42.
Which code will rename the field old_name to new_name in the data frame called data?

43.
What would the following code print ? > x <- data.frame(foo = 1:4, bar = c(T, T, F, F)) > ncol(x)

44.
In which of the following is HousePrice a data frame? (1) HousePrice <- data.frame(home=statef, postCode=zip, price=fee) (2) HousePrice <- read.table("house.data") (3) HousePrice <- scan("house.data", list("", 0, 0)

45.
___ function returns a vector of the same size as x with the elements arranged in increasing order.

46.
Consider the following code output? x = "I love R Programming" library(stringr) str_to_title(x)

47.
Which function is used to generate factor levels?

48.
___regression is used to predict the binary outcome from the given set of continuous predictor variables?

49.
How can you merge two data frames in R?

50.
What are the row names of the data frame?

51.
Which statement makes a mosaic plot ?

52.
What is the factor variable in R language?

53.
How do you create log linear models in R language?

54.
R is easily extensible through functions and ____?

55.
What is the difference between matrix and dataframe?

56.
Which of the following determines the least-squares regression line ?

57.
Let v be a vector. What is the correct way of creating a factor from v?

58.
What is the result of the following R code? > x <- c(0, 1, 2, 3, 4, 5, 6, 7) > dim(x) <- c(2,2,2) > x[,2,]

59.
What is the result of the following code? > a <- array(c(0:1, 1:0), dim=c(2,2)) > a %*% a

60.
What is the result of the following R code? > x <- array(0:7, dim=c(2,4)) > i <- array(c(1:2, 4:3), dim=c(2,2)) > x[i]

61.
How can you create scatterplot matrices?

62.
Data frames can be converted to a matrix by calling data.__

63.
What is the result of the following R code? > x <- array(0:7, dim=c(2,2,2)) > i <- array(c(1:2, 4:3), dim=c(2,2)) > x[i]

64.
How do you obtain the transpose of a matrix m in R?

65.
What is the output of the following code? > x <- c(0, 1, 2, 3, 4, 5, 6, 7) > dim(x) <- c(2,2,2) > x[1,1,2]

66.
Which of the following is lattice command for producing boxplots ?

67.
Point out the correct statement.

68.
Error is an indication that a fatal problem has occurred and __ of the function stops?

69.
What is the output of the following code? > x <- outer(1:2, 1:2, FUN = "*") > x

70.
What is the result of the following R code? > a <- array(0:7, dim=c(2,2,2)) > b<-a%*%a > b[1]

71.
While creating a data frame, the variables must have __ length?

72.
uniPlot uniforms and customizes plots of packages _ , __ and lattice?

73.
What would be the output of the following code ? > m <- matrix(1:4, nrow = 2, ncol = 2) > dimnames(m) <- list(c("a", "b"), c("c", "d")) > m

75.
What is the output of the following expression? > c(list(1), "1")

76.
What is the output of the following commands? > x <- c(0, 1, 2) > y <- x != 0 > y

77.
What is the output of the following commands? > x <- c(1, 2) > y <- c(4, 5) > pmax(x, y)

78.
What is the output of the following commands? > x <- c(1, 2) > y <- c(4, 5) > pmax(x, y)

79.
The ____ function takes an arbitrary number of arguments and concatenates them one by one into character strings?

80.
Functions are defined using the _____ directive and are stored as R objects.

81.
Which function gives the structure of a data frame “df”?

82.
What is the output of the following command? > 2*1:10