Given a set of statistical data, it is possible to represent the range, median and quartiles in one diagram known as a Box Plot or a Box and Whisker Plot.
A survey was carried out to record the weekly wages of workers at a company.
The information is shown in the box plot diagram below.
State the lowest weekly wage, the highest, the lower quartile, the upper quartile, the median and the range.
We can read the median, the lower quartile, the upper quartile, the minimum and the maximum from the diagram as follows.
Median = £280
Lower quartile = £250
Upper quartile = £350
Minimum = £150
Maximum = £500
The range = Maximum - Minimum = 500 - 150 = £350
The interquartile range = Upper quartile - Lower quartile = 350 - 250 = £100