Chapter 2: Displaying and Describing Categorical Data

Flashcards reviewing key vocabulary and concepts from the lecture notes.

Area Principle

The principle that the area occupied by a part of the graph should correspond to the size of the value it represents.

Frequency Table

A table that records the totals and the category names.

Relative Frequency Table

A table similar to a frequency table, but it gives the percentages instead of counts for each category.

Bar Chart

Displays the distribution of a categorical variable, showing the counts for each category next to each other for easy comparison.

Relative Frequency Bar Chart

Displays the relative proportion of counts for each category.

Pie Chart

A chart that shows the whole group of cases as a circle, sliced into pieces whose size is proportional to the fraction of the whole in each category.

Categorical Data Condition

The data are counts or percentages of individuals in non-overlapping categories.

Contingency Table

A table that allows us to look at two categorical variables together, showing how individuals are distributed along each variable, contingent on the value of the other variable.

Marginal Distribution

Frequency distributions for each of the variables located on the right and bottom margins of a contingency table.

Conditional Distribution

Shows the distribution of one variable for just the individuals who satisfy some condition on another variable.

Independent Variables

When the distribution of one variable in a contingency table is the same for all categories of the other variable.

Segmented Bar Chart

Displays the same information as a pie chart, but in the form of bars instead of circles; each bar is treated as the “whole” and is divided proportionally into segments corresponding to the percentage in each group.

Simpson’s Paradox

Occurs when averaging one variable across different levels of a second variable leads to misleading conclusions.