The terms average, mean, median and mode are commonly confused with each other because they all describe ways to talk about sets of numbers. To look at how each term works, let’s say that nine students took a quiz, and the scores were 91, 84, 56, 90, 70, 65, 90, 92, and 30.
When someone asks for the average of a group of numbers, they’re most likely asking for the arithmetic mean, a synonymous term. An arithmetic mean is calculated by adding several quantities together and dividing the sum by the number of quantities. For our example, we need to add the nine quiz scores together and then divide the sum by nine. So, the rounded average, or mean, score is 74.
The median is another form of an average. It usually represents the middle number in a given sequence of numbers when it’s ordered by rank. When the quiz scores are listed from lowest to highest (or highest to lowest), we can see that the median, or middle, score is 84.
The mode is the most frequent value in a set of data. For our test takers, the mode, or most common, score is 90.
Do you have any tricks for remembering what each of these four terms mean? Share in the comments!