This task was inspired by a classic written by John Mason on area and perimeter. Pupils should calculate the mean and standard deviation (non calculator) of the data set in the middle cell. They then have to create their own data sets which satisfy each of the conditions on the other cells. E.g. the top middle cell has to have the same standard deviation but a greater mean the starting cell. Pupils really have to understand the effect altering the data set has on each of the measures. A process of trial and error may be a starting point for some before more informed conjectures begin to emerge.