Analyzing Categorical Data (Section 1.1)

Vocabulary flashcards covering key terms from the section on organizing and analyzing categorical data.

Categorical data

Data classified into categories (rather than numeric values); used to describe qualities or attributes.

Bar graph

A chart that uses bars to display the distribution of a categorical variable; bars' heights correspond to frequency or relative frequency.

Pie chart

A circular chart showing the distribution of a categorical variable as slices proportional to categories’ percentages.

Two-way table

A table of counts that summarizes the relationship between two categorical variables; includes row and column totals.

Marginal relative frequency

The proportion (or percent) of observations with a given value of one variable, obtained from the margins of a two‑way table.

Joint relative frequency

The proportion (or percent) of observations that have a specific combination of values for both variables.

Conditional relative frequency

The proportion (or percent) of observations with a given value of one variable among observations that share a fixed value of another variable.

Relative frequency

The proportion of observations in a category (often expressed as a decimal or percent).

Proportion

A part of a whole expressed as a number between 0 and 1.

Percent

A proportion expressed as a percentage (out of 100).

Marginal distribution

The distribution of a single variable derived from the margins of a two‑way table.

Joint distribution

The distribution of two variables together across all combinations (shown via counts or relative frequencies).

Conditional distribution

The distribution of one variable for a fixed value of another variable.

Side-by-side bar graph

A bar graph showing the distribution of a categorical variable for each value of another variable; bars are grouped side by side.

Segmented bar graph

A bar graph where each bar is divided into segments with area proportional to category percentages.

Mosaic plot

A graphical display where rectangles’ widths reflect counts for one variable, and heights reflect categories; used to show associations.

Association (between two categorical variables)

There is an association when knowing the value of one variable helps predict the value of the other.

Causation

Causation means one variable causes changes in another; association does not necessarily imply causation.

Pictograph

A graph using pictures; can mislead due to picture size or nonuniform scaling and is generally discouraged.

Two categorical variables

Variables that classify individuals into categories and are analyzed together to study relationships via a two‑way table.

Relative frequency table

A table displaying the relative frequencies (proportions or percents) for each category.