Applications Exercises Research in Psych, 7E: Study Guide, Chapter 4 4-1

Applications Exercises Research in Psych, 7e: Study Guide, Chapter 4 4-1

Statistical Analysis

Imagine that you are in a theories of personality class with 41 other students (i.e., total of 42); in all, there are 21 males and 21 females. The instructor hands out a personality test that measures shyness on an interval scale, with scores ranging from 5 (not very shy, indeed very outgoing) to 50 (extremely shy). Here are the scores for the students in your class:

Males Females

23 36 19 26 33 43

45 39 42 19 20 32

40 37 26 17 24 26

20 34 42 35 28 22

30 29 35 30 33 27

46 41 32 29 18 26

30 36 28 34 31 37

1. For the class as a whole, calculate the mean, the median, the range, the variance, and the standard deviation.

2. For the males in the class, calculate the mean, the median, the range, the variance, and the standard deviation.

3. For the females in the class, calculate the mean, the median, the range, the variance, and the standard deviation.

4. To compare the shyness scores for males and females, use the guidelines in the online statistics guide (either by hand or with SPSS) to complete a t test for independent groups and to calculate the effect size. What can be concluded about the shyness levels of the males and females in your theories of personality class?

Answers

1. For the group as a whole:

Mean shyness score = 30.95

Median shyness score = 30.50

Range = 29.00

Variance = 60.22

Standard deviation = 7.76

2. For the males:

Mean shyness score = 33.81

Median shyness score = 35.00

Range = 27.00

Variance = 61.15

Standard deviation = 7.82

3. For the females:

Mean shyness score = 28.10

Median shyness score = 28.00

Range = 26.00

Variance = 45.02

Standard deviation = 6.71

4. Results of t test and effect size analysis:

t(40) = 2.54, p = .015

d = .55

Males are shyer than females in this class, the difference is significant, and the effect is a medium-sized one.

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