Categorical data from several groups
Useful information can sometimes be obtained by examining a single categorical distribution with a bar or pie chart. However more interesting questions can usually be asked of data when they are obtained from several groups.
Student degrees
The data may not be presented as separate lists of values from each group. The groups may equivalently be defined by a categorical variable in the original data matrix. Each 'individual' again contributes a count of 1 to a single cell of the contingency table.
Student degrees