Refresher - The Mean vs. the Median

The Mean vs. the Median

As measures of central tendency, the mean and the median each have advantages and disadvantages. Some pros and cons of each measure are summarized below.

• The median may be a better indicator of the most typical value if a set of scores has an outlier. An outlier is an extreme value that differs greatly from other values.
• However, when the sample size is large and does not include outliers, the mean score usually provides a better measure of central tendency.

To illustrate these points, consider the following example. Suppose we examine a sample of 100 individuals to estimate their income. Ninety nine of the individuals have incomes between $45,000 and $150,000; but the hundredth person has an annual income of $1,650,000,000. That hundredth person is an outlier. If we choose a measure to estimate the income of a typical person, the mean will greatly over-estimate an individual's income (because of the outlier); while the median will not.