1. Consider the following frequency distribution:
Class Interval
10 > 20
20 > 30
30 > 40 Frequency
15
25
10 What is the midpoint of the second class?
10
20
25
30
40
2. Consider the following frequency distribution: Class Interval
10 > 20
20 > 30
30 > 40 Frequency
15
25
10 What is the relative frequency of the second class?
0.15
0.30
0.50
0.20
0.40
3. A stem and leaf plot is constructed to represent the number of customer complaints received
during different time intervals. Management wants to determine what percentage of the time
they receive at least 20 but fewer than 30 calls. If the stem and leaf plot below depicts such a
collection of data, what would you report to management? 1
2
3
4
5 0
1
2
0
1
6.25%
25%
12.5%
31.25%
37.5% 1
2
2
0
1 1
3 3
3 6
2 4. A frequency distribution was created and a portion of the data was lost. You are given that
the lower class limit is 20 and the midpoint is 30. What is the upper class limit? 40
39
50
25
Cannot be determined from the information provided 5. A cumulative frequency distribution is constructed and the cumulative frequency for the third
class is 100. Assuming the frequency for the next class is not empty (i.e. 0 observations in the
class) The cumulative frequency for the next (non-empty) class will be __________ . less than 100
equal to 100
next class frequency minus 100
100 minus the next class frequency
100 us the next class frequency
6. A frequency distribution is constructed to represent the price of cars sold by a local chain of
dealerships. This information is to be used in planning for inventory levels for the coming
quarter. When the distribution was presented prior to data collection, the validity of the
distribution was brought into question. Which of the following represents the major flaw in
the design of this distribution? Class
Interval
$18,000 >
$21,000
$21,000 >
$25,000
$24,000 >
$27,000
$28,000 >
$31,000 7. Frequency There are too many
intervals.
The class widths are too
small.
Some numbers between
18,000 and 30,000
would fall into two
different intervals.
The first and the second interval overlap.
There are too few
intervals.
1. A relative frequency distribution was created from 200 observations and is presented below.
How many of the observations were greater than 200 but less than 250?
Class Interval
100 > 150
150 > 200
200 > 250
250 > 300 2.
40
80
100
20
160 Relative Frequency
20%
30%
40%
10%