1. Frequency polygons. Score 1 to 10 11 to 20 21 to 30 31 to 40 41 to 50
Frequency polygons are used to show how a set of data is distributed (the
shape of the data).
They can be used to compare two sets of data.
Example:
The table shows the scores of year 11 students in a Geography test.
Score
1 to 10
11 to 20
21 to 30
31 to 40
41 to 50
Frequency 4 8 16 20 12
Mid -point
Mid -point
5.5
15.5
25.5
35.5
45.5

2. Score
1 to 10
11 to 20
21 to 30
31 to 40
41 to 50
Frequency 4 8 16 20 12
Mid -pt
5.5
15.5
25.5
35.5
45.5

3. Score
1 to 10
11 to 20
21 to 30
31 to 40
41 to 50
Frequency 4 8 16 20 12
Mid -pt
5.5
15.5
25.5
35.5
45.5