Analysing AFL Team Age... Properly!

Mean, Median…what of it?

The mean , from Wikipedia ;

For a data set, the arithmetic mean, also called the mathematical expectation or average, is the central value of a discrete set of numbers: specifically, the sum of the values divided by the number of values.

The median , also Wikipedia ;

The median is the value separating the higher half from the lower half of a data sample (a population or a probability distribution). For a data set, it may be thought of as the “middle” value. For example, in the data set {1, 3, 3, 6, 7, 8, 9}, the median is 6, the fourth largest, and also the fourth smallest, number in the sample. For a continuous probability distribution, the median is the value such that a number is equally likely to fall above or below it.

When data is not normally distributed around the mean (as is the case here), using it to describe the measure of centre is misleading. In cases like this, the median provides a more representative statistic. With a positively skewed distribution like the one above, statistics 101 tells us that the median will be less than the average, while the opposite would hold true where the distribution was negatively skewed.

The average age of all players on team lists for the 2020 AFL premiership season is 24.17 years, while the median age is 23.6 years.