PSYCHOLOGICAL STATISTICS

1. Construct a frequency distribution table for the following set of scores. Include columns for proportion and percentage in your table.

Scores: 5, 7, 8, 4, 7, 9, 6, 6, 5, 3

9, 6, 4, 7, 7, 8, 6, 7, 8, 5

Range: 9 - 3 = 6

Classes: 7

Class Width : 9 - 3 7 = 6 7 = 0.86% round up [ = 1 ]

Class limits F Cf C%

3-4 3 3 0.15%

5-6 7 10 0.5%

7-8 8 18 0.9%

9-10 2 20 1%

11-12 0 0 0%

13-14 0 0 0%

15-16 0 0 0%

N=20

2. Complete the final two columns in the following frequency distribution table and then find the percentiles and percentile ranks requested.

X F CF C%

50-59 1 1 0.05

40-49 3 4 0.15

30-39 6 10 0.3

20-29 5 15 0.25

10-19 3 18 0.15

0-9 2 20 0.1

N=20

Lower: 50-0 Upper: 59-9

a. What is the percentile rank for X _ 9.5? 99.5

b. What is the percentile rank for X _ 39.5? 139.5

c. What is the 25th percentile? 24.5

d. What is the 50th percentile? 54.5

3. Create frequency distribution histogram for nos. 1 & 2