Which of the following statements regarding mixed vector and array arithmetic is true?

To test the residuals of a regression model X for heteroscedastisity, you can use this command:

Which is the INCORRECT way to get the vector [1 1 1 3 3 3 5 5 5]?

To test the residuals of model X for autocorrelation of first order, you can use this command:

Which is INCORRECT regarding the command: T <- 40; rnorm( T, 1, 4) ?

What is the result of command: z <- c(1:3,NA); ind <- is.na(z); z ?

Which R function will generate a mean for each row in a numeric matrix X with intermittent missing values?

In order to assess whether x and y are equal, you can use the command:

Which of the following is NOT included in CRAN's R distribution?

In a linear regression model with outcome y and linear predictors x1, x2, and x3, which R code correctly includes an interaction term between x1 and x2?

What is the output of dim(matrix(1:10, ncol=2))?