When is a pie chart used?

A pie chart is not used for sophisticated mathematical analysis. It is used to show how a given quantity is divided up, in a way can be easily seen.

A pie chart is best used when representing how the measured statistic, or "piece," fits into the whole "pie" (100%).

For example: In a family of 6, there is a father, mother, 3 brothers and 1 sister. A pie chart comparing males to females in this family would show a 72% male piece and a 38% female piece.