These four measures summarize a set of numbers in different ways.
Mean = Sum of all values ÷ Count of values
Example: (5 + 10 + 15 + 20 + 25) ÷ 5 = 75 ÷ 5 = 15.
Sort the numbers. If odd count, the middle number. If even count, the average of the two middle numbers.
Example: For 5, 10, 15, 20, 25 — median = 15. For 5, 10, 15, 20 — median = (10 + 15) ÷ 2 = 12.5.
The value that appears most often. If all values appear once, there is no mode. If multiple values tie, all are modes.
Range = Maximum − Minimum
Example: 25 − 5 = 20.