1. Cumulative Frequency & Frequency Polygons
Sunday, 18 November 2018

2. Example
The table below shows the distribution of weekly wages in two small factories
Draw a frequency polygon to represent the data
Comment on the results
Weekly wage (£)
0 - 50
Factory A 1 3 12 11 4
Factory B 5 10 8

3.
Wage (£)
Frequency 20 18 16 14 12 10 8 6 4 2
The two Frequency polygons suggest that Factory B pay lower wages on average.

4. Example
The table below shows the results in a recent survey on the weights of girls in a particular school.
Weight (w kg)
Frequency 4 15 11 10 4 19 30 40
a) Draw a cumulative frequency table and cumulative frequency curve to represent this data.
b) Find the median and interquartile range for this data.

5. Interquartile Range = 35 – 27
Weight (kg)
Cum Freq 45 40 35 30 25 20 15 10 5
b) Median = 30.5
Interquartile Range = 35 – 27
= 8