STATISTICS
Representing
Data on a Frequency Polygon
The
information in activity 4 can be represented on a frequency polygon.

Refer to
your histogram for the daily maximum temperature; identify the
frequency corresponding to 27o C.

Repeat the
procedure above for all temperatures.

Join the
plotted points with a straight edge.

What you
have joined is called a frequency polygon.
Note:

A frequency
polygon should touch the horizontal axis at both ends, crossing
at the midpoints of the first and last bars. When this condition
is not met, the resulting graph is called a line graph.

The frequency
polygon can also be drawn without first drawing a histogram
by plotting frequencies against the midmarks or class marks.
Trial
Exercise
In
a test marked out of 10, the following results were recorded.
Score

3

4

5

6

7

8

9

10

Frequency

2

3

4

7

8

6

3

1

Draw
a frequency polygon to represent the above data.

