Definition

Median of a data set

Statistics • Median

Statement

The median is the middle value of data arranged in order. For

n

observations: if

n

is odd it is the

(\frac{n + 1}{2})

th value; if

n

is even it is the mean of the

\frac{n}{2}

th and

(\frac{n}{2} + 1)

th values.

How to use it

1ORDER the data first — this is the step most often skipped.
2For a frequency distribution, use cumulative frequency to locate the middle position.
3The median is unaffected by extreme values, unlike the mean.

Find the median of

7, 3, 9, 4

Step-by-step

Answer

5.5

Watch out

The median need not be a member of the data set when

n

is even.

Also known as

middle value, positional average