What is Mean?
The mean is the sum of a set of values divided by how many there are, which is what most people call the average.
Mean explained
It is the most common summary of a column, such as average order value. Every value contributes, so one very large value can pull the mean a long way from what is typical.
That is why analysts often show the median beside the mean: a large gap between them signals skewed data.
Example
Orders of 20, 25, 30 and 425 have a mean of 125, even though three of the four orders are 30 or less.
How it differs from similar terms
The median is the middle value and is not pulled by extremes.