For questions 1-4, you will be provided with at-value, the number of degrees of freedom, alpha, and whether the test is one- or two-tailed. You will then be asked to establish the criticalt-value and state your decision regarding the null hypothesis.

1. t= 1.45,df= 12, alpha = .05, two-tailed
2. critical value oft= Decision =
3. (2 points)
4. t= 2.90,df= 22, alpha = .01, two-tailed
5. critical value oft= Decision =
6. (2 points)
7. t= 2.60,df= 17, alpha = .05, one-tailed
8. critical value oft= Decision =
9. (2 points)
10. t= 1.70,df= 13, alpha = .05, one-tailed
11. critical value oft= Decision =
12. (2 points)
13. A professor hypothesizes that students who earn a C or better in her class spend more time outside of class studying than students who receive a D or F. She collects the following data from two samples of students. What does she conclude?
14. Number of hours studying per week for C or better students: 8, 4, 4, 2, 1, 5, 3, 2, 3
15. Number of hours studying per week for D or F students: 6, 2, 1, 0, 3, 2, 1
16. Null hypothesis:
17. Alternative hypothesis:
18. Statistical test (be specific!):
19. Significance level: alpha = .05
20. degrees of freedom:
21. Critical region (t-value):
22. Calculatedt(show your work):
23. Decision:
24. (7 points)
25. A researcher decides to analyze the effects of nutrition on personality. He collects 7 pairs of identical twins and randomly assigns one twin from each pair to a controlled diet condition. The twins assigned to the other condition are allowed to eat whatever they please. The following are scores on a standardized personality inventory:
26. Personality inventory scores for twins in controlled diet condition: 10, 9, 4, 3, 8, 6, 7
27. Personality inventory scores for twins in eat-what-you-want condition: 16, 11, 9, 4, 5, 9, 12
28. NOTE: The order of the scores is important here. The first score in the controlled diet condition (10) should be paired with the first score from the other condition (16), etc.
29. Hint: This is a two-tailed test.
30. Null hypothesis:
31. Alternative hypothesis:
32. Statistical test (be specific!):
33. Significance level: alpha = .01
34. degrees of freedom:
35. Critical region (t-value):
36. Calculatedt:
37. Decision: