The median (Q2) is the middle value of a set of data, which has been arranged in order.
The lower quartile (Q1) is the median of the lower half of a set of data, once you have found the median.
The upper quartile (Q3) is the median of the upper half of a set of data.
The data below shows a sample of the percentages of pupils' test scores from Mr Brown's science class.
88 75 90 66 97 76 81
In order to find the median (Q2) of this data, we need to put them in order first.
You need to find the Median (Q2) first.