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Averages

An average is a single number that stands in for a group. There are several kinds — each tells a different story.

Mean, median, mode, range

Add numbers. Watch the four averages move with them.

35581275

Mean

6.43

45 ÷ 7

Median

5

middle value

Mode

5

most common

Range

9

max − min

Mean

Add the values, divide by how many there are. The mean is the balance point of the data.

Mean of 4, 8, 6: (4 + 8 + 6) / 3 = 6.

Median

Sort the values. The middle one is the median. With an even number of values, take the mean of the two middle ones.

Median of 3, 7, 7, 9, 12: 7. Median of 3, 7, 9, 12: (7 + 9) / 2 = 8.

Mode

The value that appears most often. A dataset can have no mode, one mode, or several.

Mode of 2, 5, 5, 5, 8, 9: 5.

Range

The biggest value minus the smallest. It tells you how spread out the data is.

Mean vs median: when it matters

Most people earn near the median wage. The mean wage is pulled up by a few very high earners. So when describing typical income, median is usually fairer than mean.