The mean, median, and mode are three different ways to describe the center or most typical value of a data set. The mean is the average, the median is the middle value, and the mode is the most frequent value.
Steps
To find the mean, add up all the numbers in your data set and divide by how many numbers there are.
To find the median, arrange all numbers in order from smallest to largest. If you have an odd number of values, the median is the middle number. If you have an even number of values, the median is the average of the two middle numbers.
To find the mode, look for the number that appears most frequently in your data set. A set can have one mode, more than one mode, or no mode if all numbers appear equally often.
Worked example
For the data set 3, 7, 5, 3, 9: Mean = (3 + 7 + 5 + 3 + 9) ÷ 5 = 27 ÷ 5 = 5.4. Median: arranged in order is 3, 3, 5, 7, 9, so the median is 5 (the middle value). Mode = 3 because it appears twice while other numbers appear once.
Remember
Mean uses all values for an average, median finds the middle position, and mode identifies the most common value.