Lauretta J. Fox
A frequency polygon is a line graph which can be used to represent the frequency of a set of numbers. It is formed by connecting a series of points. The abscissa of each point is the midpoint of the interval in which the point lies. The ordinate of each point is the frequency for the interval. The polygon is closed at each end by drawing a line from the endpoints to the horizontal axis at the midpoint of the next interval.
Example
:
Illustrate the following data on a frequency polygon:
Scores

Midpoint

Frequency

96100

98

3

9195

93

3

8690

88

4

8185

83

6

7680

78

8

7175

73

5

6670

68

3

6165

63

2

5660

58

2

Solution
:
(figure available in print form)
Exercises
:

1.) The following table shows the weekly wages earned by workers in a local hospital:
Number of People

11

11

15

18

13

12

10

Weekly Wage

$140

$200

$180

$160

$190

$150

$170

a.) Draw a histogram for the given data.
b.) Construct a frequency polygon for the given data.

2.) A baseball team made the following number of hits in a recent game:
Inning

1

2

3

4

5

6

7

8

9

Number of Hits

1

4

2

3

3

5

3

2

1

a.) Draw a dot diagram for the given data.
b.) Make a histogram for the given data.
c.) Construct a frequency polygon for the given data.

3.) The students in an English class received the following scores on a test:
60

95

85

100

81

56

87

80

62

75

73

64

69

86

93

82

77

91

58

69

76

94

72

88

78

a.) Make a frequency distribution for the given scores.
b.) Draw a histogram to represent the scores.
c.) Construct a frequency polygon for the given data.