What are the measures of central tendency?
The Mean (average) and Median (midpoint). Some will add the Mode.
For example, with the set of values: 68.4, 65.7, 63.9, 79.5, 52.5
The Mean is the arithmetic average:
(68.4 + 65.7 + 63.9 + 79.5 + 52.5)/5 = 66
The Median is the value equidistant (numerically) from the range extremes.
79.5 – 52.5 = 27 27/2 = 13.5 ; 13.5 + 52.5 = 66
NOTE: In this set of data it is the same value as the Mean, but that is not usually the case.
The mode is the most common value(s) in a set. There is none in this set (no duplicates). It is a commonly included as a statistical measure of central tendency. MY personal experience with statistics is that while it definitely can indicate a “tendency”, it is not very often a “central” one.
Other common measures applied to central tendencies are the variance and standard deviation. HOWEVER, again, these are refinements on the analysis of the data from which the central tendencies are derived. They are not themselves measures of the “central” tendency.