Statistics Chapter 10

What are the degrees of freedom for the related samples t test? (nD - 1) (n - 1) (n - 1) (n - 1) + (n - 1) (n - 1) - (n - 1)

(nD - 1)

"Elementary school children spent significantly more time reading the presence of a teacher than when the teacher was absent, t(7) = 2.804, p < .05 (ω2 = 0.46)." In this related samples t test, how many participants were observed? 5 6 7 8

8

To increase the value of estimated Cohen's d, a researcher increases the sample size. Will this change the value of d? Yes; as sample size increases, effect size increases. No; as sample size increases, effect size decreases. No; the sample size is not used to compute effect size. Yes; as sample size increases, effect size decreases.

No; the sample size is not used to compute effect size.

Each of the following is an advantage for using the related samples design, except it can be more practical it minimizes standard error it increases the power of a research design it increases the variability measured in a study

it increases the variability measured in a study

Which of the following identifies a large effect size for a t test? η2= .25 d = .76 ω2= .20 t = 2.32.

η2= .25

A researcher measures deviant behavior in a sample of 12 children from abusive homes (Sample A). Another researcher measures the same behavior in a sample of 18 children from abusive homes (Sample B). Which sample is associated with larger degrees of freedom? Sample A Sample B Each sample has the same degrees of freedom. There is not enough information to answer this question.

Sample B

Compared to the two-independent sample t test, the related samples design decreases power effect size standard error significance

standard error

Which of the following is an advantage for selecting related samples compared to selecting independent samples in behavioral research? Selecting related samples can be more practical. Selecting related samples minimizes standard error. Selecting related samples increases power. All of the above.

All of the above.

Using APA format, which value is typically given in parentheses when reporting the results for a t test? The degrees of freedom. The estimate for standard error. The value of the test statistic. The level of significance.

The degrees of freedom.

Which of the following is an assumption for computing the related samples t test? The population being sampled from is normally distributed. The population variance of difference scores is unknown. Samples are related or matched between groups, but not within groups. all of the above

all of the above

A researcher computes the mean difference in locomotion in a sample of 12 rats before and 30 minutes after an injection of amphetamine. Rats were placed in a box with infrared beams. The number of times rats crossed the beams was used as a measure of locomotion. The mean difference in locomotion was 6.2±8.4 (MD±SD), and this difference was significant. What is the effect size for this result using estimated Cohen's d? d = 0.74 (medium effect) d = 1.36 (medium effect) d = 0.74 (large effect) d = 1.36 (large effect)

d = 0.74 (medium effect)

Which of the following is the denominator of the test statistic for the related samples t test? standard error estimated standard error estimated standard error for the difference estimated standard error for difference scores

estimated standard error for difference scores

Which type of error is used to compute the confidence interval for two related samples selected from at least one population with an unknown variance? standard error estimated standard error estimated standard error for the difference estimated standard error for the difference scores

estimated standard error for the difference scores

All other things being equal, reducing the level of significance from .05 to .01 will ________ the value of the test statistic for a related samples t test. increase decrease have no effect on

have no effect on

All other things being equal, increasing the sample size will ________ the value of the test statistic for a related samples t test. increase decrease have no effect on

increase

The related samples design can ________ the power to detect an effect by making the standard error ________. increase; smaller increase; larger decrease; smaller decrease; minimal

increase; smaller

The denominator of the test statistic for a related samples t test compares mean differences observed to the mean differences stated in a null hypothesis is the sum of the difference scores for each participant provides an estimate of the error associated with the original scores provides an estimate of the error associated with the difference scores

provides an estimate of the error associated with the difference scores

type of related samples design in which participants are observed more than once is called a repeated measures design matched pairs design matched samples design both B and C

repeated measures design

Which of the following is the numerator of the test statistic for the related samples t test? the sum of the difference scores for each participant the value of the test statistic plus the degrees of freedom the mean difference observed minus the mean difference stated in a null hypothesis estimated standard error for difference scores

the mean difference observed minus the mean difference stated in a null hypothesis

To compute a related samples t test, a researcher has to know many values. Which of the following is NOT a value that the researcher must know to compute this test? the estimated standard error for difference scores the population variance of difference scores the sample size or number of pairs of scores the sample variance of difference scores

the population variance of difference scores