1. AP STATISTICS Section 4.2 Relationships between Categorical Variables

2. Objective: To be able to organize data in a two-way table and calculate marginal and conditional distributions. A two-way table is a method used to organize data from 2 categorical variables. Ex. Organize the reviews and ratings of 90 movies in a two-way table.

3. Marginal distributions are distributions created by the row/column totals. They can be given in counts or percents. They are called marginal because they can be found in the margins of the table. Use the table total to change to percents. The best way to display categorical data is through the use of a _________________. Conditional distributions are distributions that use either the row total or the column total to calculate the percentages. These distributions are found within the table. Key words: among, given, of

4. Ex. Find the marginal distribution of ratings in percents. Ex. Find the conditional distribution of reviews among the 3-star movies. Ex. Create a segmented bar chart of review for 3-star movies and 5-star movies.

5. Simpson’s Paradox: refers to a reversal of the direction of an association when data from several two-way tables is combined to form one two-way table.