1 A researcher selects a sample of 24 college students and h

1. A researcher selects a sample of 24 college students and has them rate their liking for two advertisements aimed at improving the image of the college. The researcher finds that liking ratings significantly differed, t = 2.900. Use omega-squared to compute the proportion of variance for this result.

a. ²= 0.29

b. ²= 0.24

c. ²= 0.21

d. There is not enough information to answer this question.

2. 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?

a. the estimated standard error for difference scores

b. the population variance of difference scores

c. the sample size or number of pairs of scores

d. the sample variance of difference scores

3. Two researchers analyze the same data set. Researcher A uses a two-independent sample t test and decides to retain the null hypothesis. Researcher B uses a related samples t test and decides to reject the null hypothesis. Which of the following is a likely explanation for the disparity in the decisions made.

a. The two-independent sample t test had greater power to detect the effect.

b. The two-independent sample t test was associated with fewer degrees of freedom.

c. The related samples t test had greater power to detect the effect.

d. The related samples t test was associated with more degrees of freedom.

4. \"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 (² = 0.46).\" In this related samples t test, how many participants were observed?

a. 5

b. 6

c. 7

d. 8

5. 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?

a. standard error

b. estimated standard error

c. estimated standard error for the difference

d. estimated standard error for the difference scores

6. A researcher matched 30 participants on intelligence (hence 15 pairs of participants), and then compared differences in emotional responsiveness to two experimental stimuli between each pair. For this test, what are the critical values, assuming a two-tailed test at a .05 level of significance?

a. ±2.042

b. ±2.045

c. ±2.131

d. ±2.145

7. The related samples design can ________.

a. eliminate within groups error

b. reduce power

c. increase standard error

d. be more practical

Solution

1. d. There is not enough information to answer this question.

2. b. the population variance of difference scores

3. a. The two-independent sample t test had greater power to detect the effect.

4.The number of participants were observed=7+1=8

5.d. d. estimated standard error for the difference scores

6.The critical value is t0.05,29=+/-2.045