In the last chapter, we covered a detailed example relating to a sample of profit centres in a retail organisation taken from two different regions. We saw through a variety of
diagrams that there are differences in the two sets of data and we have begun to
describe what those differences are. However, our comments have been fairly general
and somewhat imprecise. We concluded that with Region B stores there were relatively
fewer at the bottom of the profits range and relatively more at the top of the range. For
management purposes this is somewhat imprecise, to say the least. Given the manage-
ment interest in this variable, we clearly need to quantify the differences between the
two samples. For this reason we must turn to statistical measures to describe the data
rather than diagrammatic measures.