Chapter 16 Test Items

1. To conduct a t test, what is the appropriate combination of variables?

a. nominal, ordinal

b. nominal, interval/ratio

c. interval/ratio, ordinal

d. nominal, nominal

2. Wendy wants to statistically test the difference between class rank (nominal variable with four independent groups) and communication apprehension (interval variable). For what reason

should Wendy not consider use of an independent samples t test?

a. an independent samples t test cannot be used if the dependent variable is interval

b. an independent samples t test cannot be used if the independent variable has more than two independent groups

c. an independent samples t test cannot be used with a nominal independent variable

d. an independent samples t test cannot be used when investigating differences

3. Fatwah conducted a statistical test and found that t = 1.87. Each of the two groups she compared had 20 participants, and her significance level was p < 0.0005. What is Fatwah’s effect size for this study?

a. .59

b. .94

c. 1.89

d. 11.83

4. The nominal variable in a t test can have how many distinct categories?

a. one

b. two

c. three

d. four

5. If Levene’s test for equality of variances or the folded F test is significant, which of the following statements is true?

a. You cannot conduct a t test.

b. You should conduct a one-way ANOVA.

c. Equality of variances cannot be assumed.

d. Equality of variances can be assumed.

6. During a study examining female and male differences on verbal aggression, the calculated

Cohen’s d is .8. Which of the following statements is accurate based on this finding?

a. The t test was not statistically significant.

b. There is a relationship between biological sex and verbal aggression.

c. There is a small difference between females and males on verbal aggression.

d. There is a large difference between females and males on verbal aggression.

7. Which of the following illustrates the correct way to write up an independent t test using APA

format?

a. t(4.62) = 2.17, p = .06

b. t(4.62) = 2.17

c. p = .06, t(4.62)

d. t(4.62)

8. When testing for an independent samples effect size, which test formula do we use?

a. Cronbach’s alpha

b. Cohen’s d

c. Cramer’s phi

d. chi-square

9. When conducting an independent samples t test, which of the following must be true?

a. Both variables must be nominal.

b. Both variables must be interval.

c. At least two variables must be ratio.

d. One variable must be nominal (with two categories), and one must be interval.

10. Which of the following assumptions of the independent samples t test is not accurate?

a. The dependent variable must be an interval or ratio variable.

b. The independent variable must be a nominal variable.

c. The dependent variable need not be normally distributed in both of the independent variable levels.

d. A sample should be drawn from populations with equal variances on the dependent variable.

For questions 11 to 17, use the t test results that are presented below. A researcher wanted to examine differences between male (1) and female (2) verbal aggression scores. Here are the data he found:

Male 1: 89

Male 2: 90

Male 3: 120

Male 4: 120

Male 5: 77

Female 1: 74

Female 2: 120

Female 3: 20

Female 4: 65

Female 5: 80

11. In the t test presented, what were the degrees of freedom?

a. 8

b. 6.21

c. .17

d. .18

12. In the t test presented, what is the correct write-up for Levene’s test for equality of variances?

a. (F = .36, p > .05)

b. (F = .36, p < .05)

c. (F = 1.50, p = .17)

d. (F = 1.50, p = .18)

13. In the t test presented, what is the calculated value?

a. 1.50

b. .36

c. .56

d. 5.21

14. In the t test presented, what was the calculated p value?

a. .17

b. .18

c. < .05

d. .56

15. In the t test presented, which of the following statements is correct?

a. The t test was not statistically significant.

b. The t test was statistically significant.

c. The t test reported a large effect size.

d. The t test reported a small effect size.

16. In the t test presented, how would you categorize the p value?

a. p > .05

b. p < .05

c. p < .01

d. p < .005

17. In the t test presented, which of the following is the correct APA write-up?

a. t(8) = 1.50, p = .17

b. t(5.21) = 1.50, p = .18

c. t(8) = .36, p < .05

d. t(5.21) = .36, p > .05

18. In real-world situations, it is recommended that each nominal category of an independent variable used in a t test has at least how many participants?

a. 30

b. 15

c. 50

d. 25

19. If a t test is statistically significant, what test do you need to calculate by hand?

a. Cohen’s d

b. Cohen’s kappa

c. Cronbach’s alpha

d. Cramer’s V

20. Julian is in the process of calculating a t test. After finding out that his t test was statistically significant, he conducts an effect size test. The calculated value he receives is .59. How would you interpret the effect size?

a. medium effect size

b. small effect size

c. large effect size

d. enormous effect size

21. At the p < .05 level, if the critical value is 2.306 and the calculated t statistic is 2.169, the t test is statistically significant at the p < .05 level.

a. True

b. False

22. If any assumption of the independent t test is violated, the meaning of the t test is lost.

a. True

b. False

23. If a t test is not statistically significant, a researcher must accept the null hypothesis.

a. True

b. False

24. A statistical program (such as SPSS) may be used to interpret independent t test statistics.

a. True

b. False

25. If equal variances cannot be assumed, the t test should be tweaked.

a. True

b. False

26. The independent samples t test allows a researcher to examine the differences on an interval or ratio variable between two nominal variables.

a. True

b. False

27. When conducting a t test, the independent variable must be a nominal variable.

a. True

b. False

Essays:

28. Explain the purpose of a t test.

29. Explain the purpose of Cohen’s d.

30. Explain the assumptions of the independent samples t test.

31. Interpret the t test results that are provided below. In this study, the researchers were examining if female and male participants differed in their levels of communication apprehension when interacting with police.

Matching:

32. Match each of the following terms with the correct statement.

a. Cohen’s d = Used to test for an independent samples effect size.

b. Paired t Test = Used to compare two interval/ratio level scores that are taken from the same group at two distinct time periods.

c. Independent Samples t Test = Examines one nominal variable with two categories and their scores on one dependent interval/ratio variable.