Statistics for the Behavioral Sciences by Frederick J. Gravetter, Larry B. Wallnau ISBN 10: 1305504917 ISBN 13: 9781305504912

APPENDIX C | Solutions for Odd-Numbered Problems in the Text 667
5.
X z X z X z
45 0.45 52 1.09 41 0.09
30 −0.91 25 −1.36 38 −0.18
7. a.
X z X z X z
69 0.75 84 2.00 63 0.25
54 −0.50 48 −1.00 45 −1.25
b.
X z X z X z
66 0.50 78 1.50 30 −2.50
57 −0.25 54 −0.50 75 1.25
9. a. X = 41
b. X = 42
c. X = 44
d. X = 48
11. σ = 6
13. σ = 4
15. a. central (z = 0.67)
b. extreme (z = 2.50)
c. central (z = −0.25)
d. extreme (z = −2.67)
17. a. X = 70 corresponds to z = −1.50, and X = 60
corresponds to z = −1.00 (better grade).
b. X = 58 corresponds to z = 1.50, and X = 85
corresponds to z = 1.50. The two scores have the
same relative position and should receive the same
grade.
c. X = 32 corresponds to z = 2.00, and X = 26 corresponds
to z = 3.00 (better grade).
19. a. X = 75 (z = −1.25)
21.
b. X = 90 (z = −0.50)
c. X = 115 (z = 0.75)
d. X = 130 (z = 1.50)
X z X z X z
32 0.25 34 0.50 36 0.75
28 20.25 20 21.25 18 21.50
23. M = 53
25. μ = 50 and σ = 6. The distance between the two
scores is 9 points which is equal to 1.5 standard
deviations.
CHAPTER 6
Probability
1. The two requirements for a random sample are: (1)
each individual has an equal chance of being selected,
and (2) if more than one individual is selected, the
probabilities must stay constant for all selections.
3. a. p = 1 3 = 0.33
b. p = 2 3 = 0.67
c. p = 2 3 = 0.67
5. a. tail to the right, p = 0.1587
b. tail to the right, p = 0.3085
c. tail to the left, p = 0.1056
d. tail to the left, p = 0.3446
7. a. p(z > 1.25) = 0.1056
b. p(z > −0.60) = 0.7257
c. p(z < 0.70) = 0.7580
d. p(z < −1.30) = 0.0968
9. a. p = 0.5762
b. p = 0.5328
c. p = 0.3539
d. p = 0.0968
11. a. z = ±0.39
b. z = ±0.52
c. z = ±0.67
d. z = ±0.84
13. a. body to the left, p = 0.5987
b. body to the right, p = 0.8413
c. body to the right, p = 0.6915
d. body to the left, p = 0.7734
15. a. z = 1.38, p = 0.0838
b. z = −1.13, p = 0.1292
17. a. p(z < −1.00) = 0.1587
b. p(z > 1.50) = 0.0668
c. z = 0.84, X = 584
19. a. p(z > 1.80) = 0.0359
b. p(−1.00 < z < 1.00) = 0.6826