# PSY 300 USC Beaufort Statistics for the Behavioral Sciences Worksheet

Psy 300 – Statistics for the Behavioral Sciences

Homework 2

A distribution of scores is normal with M = 45 and s = 8. Find the z-scores that correspond to the following raw scores:

1. X = 32

2. X = 47

z=

z=

For the same distribution, find the raw scores that correspond to the following z-scores:

3. z = 2.6

4. z = -1.4

X=

X=

5. Stan and Lia both took a History test in different classes. Stan’s score was 82 with a class distribution of M=80 and s=6.

Lia scored a 78 with a class distribution of M=76 and s=4. Using z-scores, explain why Lia did “better” on the test even

though her raw score was lower.

Find the following:

6. p(z < 1.9) =
7. p(z < -2.1) =
8. p(z > 1.3) =

9. p(z > -.9) =

Given a normal distribution with M = 200 and s = 20, find the following:

10. The z-score equivalent for a raw score of 240 =

11. p(X > 240) =

12. The z-score equivalent for a raw score of 165 =

13. p(X > 165) =

14. The z-score that separates the top 10% of scores =

15. The raw score that separates the top 10% of scores =

16. The z-score that separates the top 75% of scores =

17. The raw score separates the top 75% of scores =

18. The z-score separates the bottom 40% of scores =

19. The raw score that separates the bottom 40% of scores =

20. The z-score equivalent for a raw score of 172 =

21. The percentile for a raw score of 172 =

22. The z-score equivalent for the 85th percentile =

23. The raw score equivalent for the 85th percentile =

Here are special symbols that may be needed for the following problems (copy and paste them as needed): ±

You may also need to remove subscripts and italics when you type your answers. In Word, use the Font menu on the

Home tab to do this.

A researcher hypothesizes that this season’s football players (n=25) have higher aggression levels than last season’s

players. On an aggression survey, the average score for this season is 35.7 with s= 5.1. Last season, the mean aggression

score on the survey was 30. Find the following, using =.05:

24. HO:

25. H1:

26. df =

27. tcrit =

28. sM =

29. M- =

30. tobt =

31. Decision regarding HO:

32. Interpretation in APA format:

33. r2 =

Students from a college emphasizing “green” living were hypothesized to differ in conservation activity participation

compared to students from other colleges. A sample of 6 students from the “green” college participated in conservation

activities an average of 15 times over the past year (s=5.7). The overall average among college students is 12. Find the

following, using =.05:

34. HO:

35. H1:

36. df =

37. tcrit =

38. sM =

39. M- =

40. tobt =

41. Decision regarding HO:

42. Interpretation in APA format:

43. d =

Extra credit (1 point): In a normal distribution, what percentile corresponds to the median?

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