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

38 CHAPTER 2 | Frequency Distributions
LEARNING CHECK
1. For the following frequency distribution, how many individuals had a score of
X = 2?
a. 1
b. 2
c. 3
d. 4
X
5 1
4 2
3 4
2 3
1 2
f
2. The following is a distribution of quiz scores. If a score of X = 2 or lower is failing,
then how many individuals failed the quiz?
a. 2
b. 3
c. 5
d. 9
X
3. For the following frequency distribution, what is ΣX 2 ?
a. 30
b. 45
c. 77
d. (17) 2 = 289
f
5 1
4 2
3 4
2 3
1 2
X
4 1
3 2
2 2
1 3
0 1
f
ANSWERS
1. C, 2. C, 3. B
2.2 Grouped Frequency Distribution Tables
LEARNING OBJECTIVE
When the scores are
whole numbers, the total
number of rows for a
regular table can be
obtained by finding the
difference between the
highest and the lowest
scores and adding 1:
rows 5 highest
2 lowest 1 1
3. Identify when it is useful to set up a grouped frequency distribution table, and explain
how to construct this type of table for a set of scores.
When a set of data covers a wide range of values, it is unreasonable to list all the individual
scores in a frequency distribution table. Consider, for example, a set of exam scores that
range from a low of X = 41 to a high of X = 96. These scores cover a range of more than
50 points.
If we were to list all the individual scores from X = 96 down to X = 41, it would take
56 rows to complete the frequency distribution table. Although this would organize the
data, the table would be long and cumbersome. Remember: The purpose for constructing
a table is to obtain a relatively simple, organized picture of the data. This can be accomplished
by grouping the scores into intervals and then listing the intervals in the table
instead of listing each individual score. For example, we could construct a table showing
the number of students who had scores in the 90s, the number with scores in the 80s, and