Estimating the mean and median 'by eye'

Half of the values in a data set are below the median and half are above.

The data set's mean would be the point of balance if the crosses in a dot plot had equal mass.

In the following diagram, there are two vertical lines corresponding to your guessed values for the mean and median of the values represented by the stacked dot plot. Drag the mean and median to the correct values.

Repeat until you can 'guess' the values of the mean and median consistently.