How it works
The mean (average) adds up every value and divides by how many there are.
The median is the middle value once the list is sorted, or the average of the two middle values if there is an even number of values.
The mode is whichever value (or values) occurs most often. If every value occurs equally often — including when no value repeats at all — there is no mode.
The range is the largest value minus the smallest.
Formula: Mean = sum ÷ count. Median = middle value once sorted. Mode = most frequent value(s). Range = largest − smallest.
Examples
A list with a repeated value
For 2, 4, 4, 6, 8: the mean is 4.8, the median is 4, the mode is 4 (it appears twice), and the range is 8 − 2 = 6.
Things to keep in mind
- The mean can be pulled higher or lower by a few unusually large or small values in the list; the median is not affected the same way, which is why the two can differ noticeably.
- A list can have more than one mode (it is "multimodal") when two or more values are tied for the highest frequency.
- A list where every value is different has no mode, since no single value occurs more often than the rest.