AP Stats Lesson 1.1 & 1.2 Vocabulary

Vocabulary flashcards covering key concepts from AP Stats Lesson 1.1 and 1.2 (data types, variables, graphs, and tables).

Categorical (qualitative) variable

A variable that places observations into named categories or labels (uses words; examples: student ID, favorite class, league).

Quantitative (numerical) variable

A variable that takes numeric values representing amounts or counts (examples: test scores, stadium capacity, number of students).

Individual

A single object described by data in a data set (e.g., a baseball team).

Explanatory variable

The variable used to explain or predict the outcome; the input or factor being studied (often denoted X).

Response variable

The outcome measured in response to the explanatory variable; the dependent variable (often denoted Y).

Bar graph

A chart that uses bars to display the frequency or relative frequency of categories in a categorical variable.

Relative frequency

The proportion or percent of observations in a category (frequency divided by total).

Frequency

The count of observations in a category.

Segmented bar graph

A bar graph divided into segments representing subcategories; used to compare distributions across groups.

Mosaic plot

A graphical display of two or more categorical variables using rectangles whose areas are proportional to joint frequencies; shows association patterns.

Two-way table

A table that shows counts for two categorical variables, with rows and columns representing their levels.

Association

A relationship between two categorical variables where the distribution of one variable differs across levels of the other.

No association

There is no evident relationship between the variables; distributions are similar across levels.

Proportion

A part of the total; a ratio of a subset to the whole (e.g., proportion of private colleges in a state).

Population

The entire group of individuals or items that could be studied.

Sample

A subset of the population selected for analysis.

Frequency distribution

A table or chart that shows the counts of observations in each category or class.