Displaying+and+Describing+Categorical+Data

There are various ways to display and describe categorical data. Among these include frequency tables, bar charts, pie charts, and contingency tables.


 * **Frequency Tables**
 * Lists categories based upon their categorical variable and lists their counts or percentages based upon categories.
 * **Bar Charts**
 * Represents the count of each category by the same amount of area
 * **Pie Charts**
 * Divides the whole into categories through the use of wedges in a circle corresponding to the proportion in the category
 * **Contingency Tables**
 * Displays counts or percentages of individuals into specific categories on multiple variables. The individuals are categorized on all variables at once to show patterns that may be contingent on the category of another


 * Ways to show data in contingency tables are marginal and conditional distribution.
 * __Marginal distribution__ uses the margins of the table on both the right and bottom, they both give totals.
 * __Conditional distribution__ is used to show one variable for only those individuals satisfying some condition on another variable.
 * **Independence**
 * The distribution for one variable is the same for all categories of another


 * **Simpson's Paradox**
 * When averages are taken across different groups, they appear to be contradictory


 * **Area Principal**
 * The area of the bar, wedge, or illustration on a graph should be proportional to the data it represents.
 * **Distribution**