Central Tendency Measures

What they are:

Central tendency measures tell us what is a typical score in a distribution.

MODE:

The most frequent score.

MEDIAN:

The middle score if we arrange scores from lowest to highest.

MEAN:

The average that we calculate by adding up all the scores and dividing by the number of scores we added.

Which central tendency measure you can use depends on the level of measurement your scores represent:

Level of Measurement	MODE	MEDIAN	MEAN
Nominal	Yes	No	No
Dichotomies	Yes	No	Yes
Ordinal	Yes	Yes	No*
Interval/Ratio	Yes	Yes	Yes

* Ordinal variables are often treated as if they were interval variables. The rule of thumb is that if you have at least five ordered categories and there is no reason to believe that these categories are not evenly spaced, you can treat them as interval variables.