Contingency tables are frequency tables represented by two or more categorical variables along with the proportion of each class represented as a group. Frequency table is used to represent one categorical variable; however, contingency table is used to represent two categorical variables.
Let's see an example to understand contingency tables, bivariate statistics, and data normality using the
> table(Cars93$Type) Compact Large Midsize Small Sporty Van 16 11 22 21 14 9 > table(Cars93$AirBags) Driver & Passenger Driver only None 16 43 34
The individual frequency table for two categorical variables
Type of the car is represented previously: ...