The Psychology of Quality and More

Median

The median can be found by sorting the numbers into numeric order and selecting the middle number. If there are an even number of numbers, then the average of the middle two numbers is used. Thus the median of 1 2 4 5 6 is 4, and the median of 1 2 4 5 is 3.

The advantage of the median is that it is not affected by outlier numbers (like 256 in the lists above). However, it is only one number and does not take the value of the other numbers into account.

Whilst the Median gives a measure of central tendency, the common method of measuring the spread of a set of numbers is the Standard Deviation.

Other methods of measuring central tendency are Mean (or Average) and Mode.

See also:

Toolbook chapter: Variation