Please use the following information for next 6 questions.

A social psychologist is interested in whether women from the U.S. say they have higher religious freedom than women from other countries. The researcher asks a sample of 15 women from the U.S. and 15 women from other countries to rate their religious freedom on a scale of 1 to 100 (total N = 30). The sample means for religious freedom from these groups are 55 and 51 respectively. The researcher will use the independent sample t-test to analyze the data.

1. What are the total degrees of freedom for the independent t-test?

a. 13

b. 28

c. 29

d. 14

Question 21

If the standard error, or the standard deviation of the distribution of differences between means (Sdiff) is .86, what is the sample t score (tobs)?

a. 2.33

b. .727

c. 6.4

d. 4.65

Question 22

What is the critical value of t (tcrt) for the study listed above (assume a two-tailed test and alpha level of .05)?

a. 1.96

b. 1.701

c. 2.65

d. 2.049

Question 23

Comparing your observed t value (tobs) from question 21 to the critical value (tcrt) from the previous question, what can you infer about the study?

a. The researcher cannot reject the null hypothesis; there are no significant differences between groups

b. The researcher can reject the null hypothesis; there are significant differences between groups

c. There is insufficient data to conclude that there is a significant difference between groups

d. The researcher can state that there are differences between groups, but they were not in the predicted direction, therefore it is not significant

Question 24

Calculate Cohen's d effect size for the above data.The sample standard deviation is 8.

a. .8

b. .5

c. cannot compute

d. .2

Question 25

Is the effect size a small, medium or large effect size?

a. cannot compute

b. small

c. large

d. medium

Question 26

In which situation would you use a t-test for independent means?

a. to compare mean levels of anxiety in a group of students before taking an anti-anxiety pill and then again after taking it.

b. to compare mean levels of reading comprehension in students from public schools vs. private schools.

c. to find the relationship between how much coffee people drink and how much they sleep.

d. comparing grade averages in children when they are in 3rd grade, and then again when they are in high school.