The most frequently quoted remark about statistics is probably: "There are lies, damned lies and statistics." The danger of interpreting percentages is beautifully illustrated by the invention of an imaginary advertisement for a "Rabbitburger". Everyone knows what a Hamburger is. The Rabbitburger, it was claimed, was 50 percent rabbit and 50 percent horse, which investigation reveled as meaning that it was made from ration of meat of one rabbit to one horse!

Percentages do not present us with much difficulty so long as we remember what percentage of what we are talking about. Averages may be more difficult in that we have to know what kind of average our statistician is feeding us with.

For example, if we have ten guinea-pigs, and we divide the total weight of the animals, we should arrive at the mean weight. However, if in our sample group there happened to be a giant-size guinea-pig, he would distort the average (i.e. mean), so as to make it meaningless statistics.

Similarly, one underfed guinea-pig in the sample would cause a deviation from the mean, although it would not distort the mean as much as the giant weighing many times more than the average. In order that the average should not be unduly distorted causing a distortion as against normal distribution curve, we can ignore the exceptions but then we no longer have a mean average, but a median.

In addition, should we for some reason want to fit all our guinea-pigs with woolly jackets and not want to have to buy too many different sizes, we must find out which size occurs most frequently and that size will be neither the mean not the median; it will be the mode.