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 mid-points 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 mid-marks 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.
|
|
