Mode vs Mean

The mode is simply the most common value, the tallest bar or highest peak in a distribution. For example, in the data set 2, 4, 4, 7, 9 the mode is 4 because it occurs twice while every other value occurs once. A data set can have no mode, one mode, or several modes, and the mode is the only center that also works for categorical data like favorite color. Unlike the mean, the mode does not require the values to be numbers.

The mean is the balance point of a distribution, the value where the data would balance if placed on a seesaw. For example, the mean of 4, 8, and 9 is $(4 + 8 + 9) / 3 = 7$. The sample mean is written $\bar{x} = \frac{1}{n}\sum x_i$, where $\sum x_i$ (the sum of the values) is divided by $n$ (the number of values). Because every value contributes, the mean is sensitive to outliers and skew.