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 Whisper Plot.

**Example**

A survey was carried out to record how much time children in a class spent texting on their mobile phones one day.

The times (in minutes) are as follows:

0, 2, 4, 1, 0, 5, 10, 3, 4, 5, 9, 14, 13, 5, 4, 6, 10, 0, 2, 4

Draw a box plot to display this information.

**Answer**

First we must work out the median, the lower quartile, the upper quartile, the minimum and the maximum.

Place the times in order.

0, 0, 0, 1, 2, 2, 3, 4, 4, 4, 4, 5, 5, 5, 6, 9, 10, 10, 13, 14

The median of the 20 numbers is the mean of the 10th and 11th numbers.

The lower quartile is the median of the lower 10 numbers.

The upper quartile is the median of the upper 10 numbers.

**Median = 4**

**Lower quartile = 2**

**Upper quartile = 9.5**

**Minimum time = 0**

**Maximum time = 14**