1. Using a histogram to estimate the median
Histograms
Using a histogram to estimate the median

2. Draw a histogram to represent the data
Example
The distribution below represents the examination marks of 120 students.
Mark
0 –20
20 –30
30 –35
35 –45
45 –55
55 –70
Frequency 9 12 20 29 27 23
Draw a histogram to represent the data
Use the histogram to estimate the median.

3. 2 4 10 20 30 40 50 60 70
Mark

4. Example
The following table gives the heights of 80 children.
Draw a histogram to represent this information.
Using the histogram estimate the height by which 20% of the children exceed.
Height (cm)
Frequency
130 – 135 5
135 – 140 7
140 – 150 15
150 – 160 29
160 – 165 13
165 – 170 10
170 – 175 1

5. 120
130
140
150
160
170
180
Mark