A concept which may need a bit more explanation is: which average is appropriate for a given question? What is the best measure of central tendency? When would you use a median instead of a mean, or perhaps use a mode instead?

For any data set, you can perform the analysis to come up with a value for each average. However, here are a few basic guidelines to help you choose the most appropriate form of central tendency to describe your data.

**1. For a normal, random distribution of data (evenly distributed), the mean is preferred.**

**2. For a skewed data set, a median is more appropriate than a mean. The skewed data set (ie. extreme data points) will cause the mean value to be much more extreme than the median, and therefore less central.**

**3. The mode can be used for non-numerical data. Eg. hair colour in a classroom.**

Here are a few examples of where each would be appropriate:

**Mean**:

- students’ heights in a classroom
- temperature over a length of time

**Median**:

- income of a group of people
- test scores for a group of students

**Mode**:

- finding the most common hair colour in a room
- finding the most common car in a parking lot

Hopefully these guidelines will help you to determine which is the most appropriate measure of central tendency to report for your data set.