Which of the following is NOT a measure of variability?

The mean is a measure of central tendency, which summarizes a set of data points with a single value that represents the average of that set. It provides information about where the center of the data lies, but it does not convey how spread out the data points are from that center.

In contrast, measures of variability, such as range, standard deviation, and variance, are designed to indicate the extent to which data points differ from each other and from the mean. The range gives the difference between the highest and lowest values, while standard deviation and variance quantify the average distance of each data point from the mean, providing a clearer picture of data spread. Thus, the mean does not reflect variability, making it the correct answer for this question.