Statistics Quiz # 13

What is the critical value?

The outer end of the region of rejection

The inner edge of the region of rejection

The absolute value of the entire region of rejection

The value of z needed to conclude that the population mean occurred by chance

A parametric inferential statistical test of the null hypothesis for a single sample where the population variance is known is the ______.

T test

Standard deviation

Z-test

Standard error test

The sampling distribution is a distribution of ______ means based on random ______ of a fixed size from a ______.

Population; samples; population

Sample; samples; population

Population; populations; sample

Sample; populations; sample

If an independent-groups t-test has 13 subjects in each group, then the degrees of freedom are _____.

26

24

13

12

For an independent-groups t-test, the value of Cohen’s d describes _____.

The size of the treatment effect

The chance of a Type I error

The chance of a Type II error

The overall chance level in the experiment

Degrees of freedom (df) for the one-sample t-test is equal to _____.

Df - 1

N - 1

N

N + 1

If the null hypothesis is TRUE, then the t-test should be close to _____.

0.00.

±1.65.

±1.96.

±3.00.

In an independent groups t-test, we divide by _____.

The standard error of the mean

The estimated standard error of the mean

The standard deviation

The standard error of the difference between means

If, after calculating an independent-groups t-test you find that it is equal to zero, then _____.

The two-sample means differ significantly

The two-sample means do not differ significantly

You have done something wrong

The two population means differ significantly

For an independent-groups t-test, effect size can be measured using _____.

Cohen’s d

The standard error of the difference between means

R2

Either Cohen’s d or r2

In order to compute the t value, you must approximate the sample size by calculating the ______..

Pooled variance

Degrees of freedom

Critical value

Directional hypothesis

What happens to the t-distribution as the sample size increases?

The t-distribution appears less and less like a normal distribution.

The t-distribution appears more and more like a normal distribution.

The shape of the t-distribution is unaffected.

Becomes nearer to the true value of µ

T(14) = 3.35, one-tailed. Based on these results we ______.

Reject Ho

Fail to reject Ho

Accept Ho

Reject Ha

As sample variance ______, the value of the t-test ______.

Increases; increases

Decreases; decreases

Increases; decreases

Increases; stays the same

An independent-groups t-test _____.

Compares sample means for two related groups

Compares sample means for two unrelated groups

Compares standard deviations for two unrelated groups

Compares sample means for three or more unrelated groups

If the null hypothesis is NOT supported, then the t-test should be _____.

0.00.

±1.00.

Greater than ±1.00.

A negative number

Which of the following t-test results has the greatest chance of statistical significance?

T(28) = 1.70

T(14) = 1.70

T(18) = 1.70

T(10) = 1.70

If a researcher reported for a one-tailed single-sample t-test that t(14) = 2.25, then _____.

P < 0.025

P < 0.05

P < 0.01

P < 0.001

When computing the t value, the sample size must be approximated by calculating the ______.

Pooled variance

Mean score

Standard deviation

Degrees of freedom

Which of the following is NOT an assumption of the t-test?

The data should be ordinal or nominal.

The population distribution of scores should be symmetrical.

The population mean (µ) is known, but the population standard deviation (σ) is not known.

The sample size is typically less than 30.

If the obtained value is greater than the critical value, what should be done?

Reject the null hypothesis

Set a higher p value

Accept the null hypothesis

Increase the sample size

For a single-sample t test with 18 subjects, the degrees of freedom are _____.

17

18

16

Unable to be determined

If a researcher reported for a single-sample t-test that t(17) = 2.90, p< 0.02, how many subjects were there in the study?

18

20

10

9

The set of distributions that although symmetrical and bell-shaped, are NOT normally distributed is known as _____.

Student’s t distribution

Gosset’s t distribution

The z distribution

None of these

If a researcher reports a one-sample t-test with df = 24, how many individuals participated in this study?

24

25

26

Cannot be determined from the information given

A parametric inferential statistical test of the null hypothesis for a single sample where the population variance is NOT known is the ______.

Z test

T test

Cohen’s d

Standard error of the mean

What happens to the t-distribution as the sample size increases?

The t-distribution appears less and less like a normal distribution.

The t-distribution appears more and more like a normal distribution.

The shape of the t-distribution is unaffected.

Becomes nearer to the true value of mu.

The number of scores in a sample that are free to vary represents ______.

The sample size

N

The degrees of freedom

None of these

Degrees of freedom (df) for the one-sample t-test is equal to _____.

N + 1

N - 1

N.

1/N

Which of the following is NOT TRUE of the analysis of variance?

It has a higher rate of Type I error than the two-sample t-tests.

It determines whether significant differences exist in an experiment.

It is used for experiments with two or more sample means.

It is a parametric procedure.