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Mean, median and mode

The mean is the sum divided by the count, and one very high value pulls it up. The median is the middle value once the numbers are sorted. For an even count it is the average of the two middle ones. The mode is the value that occurs most often. The median often describes the typical case better when one number is extreme. The mean is still correct as a calculation, it just answers a different question.

xˉ=sumn\bar x = \frac{\text{sum}}{n}mean
median\text{median}middle sorted value

Symbols

nnnumber of values

Example

Pay 25, 27, 28, 30 and 90: mean 25+27+28+30+905=40\dfrac{25 + 27 + 28 + 30 + 90}{5} = 40, median 28.

The numbers 4, 6, 8 and 10 have mean 4+6+8+104=7\dfrac{4 + 6 + 8 + 10}{4} = 7.

In 2, 3, 3, 5, 3, 7, 2 the mode is 3.

The median is the middle value after sorting. It is not a further calculation beyond that.
Practise statistics for free →

Range and standard deviation →

Part of Mathematics 2P: Statistics.