Pie Chart
Pie charts (the term first used by Haskell, 1922) are useful for representing proportions. Individual data values of the Xvariable are represented as the "wedges" of the pie.
The sequence of values from the selected variable will be represented by consecutive slices of the pie (this term was first used by Haskell, 1922); the size of each slice will be proportional to the respective value. The values should be greater than 0 (0's and negative values cannot be represented as slices of the pie). This simple type of pie chart (sometimes called data pie chart) interprets data in the most straightforward manner: one case = one slice.
Source: Statistica
