Best Measure of Center
What is the best measure of center? There is no single best answer to this question.
The table below shows a comparison of mean, median, mode, and midrange.
Measure of center (Average) |
Definition |
Does it exist? |
Takes every value into account? |
Affected by extreme values |
How often is it used? |
Mean |
|
Always exists | yes | yes | Used a lot |
Median |
Number in the middle | Always exists | no | no | Commonly used |
Mode |
Most frequent number(s) | May not exist. May be more than one mode. | no | no | Sometimes used |
Midrange |
|
Always exists | no | yes | Rarely used |
As you can see in the table above, these measures of center have some similarities and differences.
As a rule of thumb, the best measure of center may depend on the kind of data set you have.
- When do I use the mean? If it is important to include all the values and there are no extremes values, then use the mean.Generally speaking, this is your first choice.
- When do I use the median? If there are some extreme values and not many values that repeat themselves, then use the median.
- When do I use the mode? If there are many values that repeat themselves, then use the mode.
- When do I use the midrange? If there are absolutely no extreme values, no repeated values, and you want to get an a quick answer for the measure of center, use the midrange. This is your last resort!