The median finds the middle — Data, 11–13 years
The median is the middle value after the data has been put in order. It can describe a typical result without being pulled strongly by one unusually large or small value.
What the median is
Put all the values in order from smallest to largest. The median is the value with the same number of values on each side. If there are two middle values, take their mean so the centre is shared fairly.
Why use the median?
A mean can be dragged upwards by one enormous value, such as a billionaire’s wealth in a list of incomes. The median answers a different question: what value is in the middle of the people or objects being compared?
Finding a median
Five friends wait 3, 4, 5, 6 and 30 minutes for a bus. The values are already ordered, so the third value is the median: 5 minutes. The mean is 9.6 minutes, pulled up by the 30-minute wait.
The middle is not always the mean
A common mistake is to add the values and divide, even when the question asks for the median. That feels reasonable because both numbers describe a centre, but they are built differently: the median uses position, while the mean uses every value.
Median outside school
News reports often use the median price of homes or the median income in a place. This helps describe what a person near the middle might experience, especially when a few very expensive homes or very high incomes would distort the mean.
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