21. Data that provide labels or names for categories of like items are known as
a. qualitative data
b. quantitative data
c. label data
d. category data

22. A tabular method that can be used to summarize the data on two variables simultaneously is called
a. simultaneous equations
b. crosstabulation
c. a histogram
d. an ogive


23. A graphical presentation of the relationship between two variables is
a. an ogive
b. a histogram
c. either an ogive or a histogram, depending on the type of data
d. a scatter diagram


24. A histogram is said to be skewed to the left if it has a
a. longer tail to the right
b. shorter tail to the right
c. shorter tail to the left
d. longer tail to the left


25. When a histogram has a longer tail to the right, it is said to be
a. symmetrical
b. skewed to the left
c. skewed to the right
d. none of these alternatives is correct


26. In a scatter diagram, a line that provides an approximation of the relationship between the variables is known as
a. approximation line
b. trend line
c. line of zero intercept
d. line of zero slope


Exhibit 2-1
The numbers of hours worked (per week) by 400 statistics students are shown below.

Number of hours Frequency
0 - 9 20
10 - 19 80
20 - 29 200
30 - 39 100

27. Refer to Exhibit 2-1. The class width for this distribution
a. is 9
b. is 10
c. is 39, which is: the largest value minus the smallest value or 39 - 0 = 39
d. varies from class to class


28. Refer to Exhibit 2-1. The number of students working 19 hours or less
a. is 80
b. is 100
c. is 180
d. is 300


29. Refer to Exhibit 2-1. The relative frequency of students working 9 hours or less
a. is 20
b. is 100
c. is 0.95
d. 0.05


30. Refer to Exhibit 2-1. The percentage of students working 19 hours or less is
a. 20%
b. 25%
c. 75%
d. 80%


31. Refer to Exhibit 2-1. The cumulative relative frequency for the class of 20 - 29
a. is 300
b. is 0.25
c. is 0.75
d. is 0.5


32. Refer to Exhibit 2-1. The cumulative percent frequency for the class of 30 - 39 is
a. 100%
b. 75%
c. 50%
d. 25%


33. Refer to Exhibit 2-1. The cumulative frequency for the class of 20 - 29
a. is 200
b. is 300
c. is 0.75
d. is 0.5


34. Refer to Exhibit 2-1. If a cumulative frequency distribution is developed for the above data, the last class will have a cumulative frequency of
a. 100
b. 1
c. 30 - 39
d. 400


35. Refer to Exhibit 2-1. The percentage of students who work at least 10 hours per week is
a. 50%
b. 5%
c. 95%
d. 100%


36. Refer to Exhibit 2-1. The midpoint of the last class is
a. 50
b. 34
c. 35
d. 34.5