AP Statistics - Data Analysis Introduction

Individual

An object described in a set of data.

Variable

An attribute which can take different values for different individuals

Categorical Variable

A qualitative variable that cannot be averaged.

Quantitative Variable

A numeric variable that can be averaged.

Discrete Variable

A fixed set of values with a minimum gap between values; can list all possible values easily.

Continuous Variable

A variable that can take any value of an interval on a number line.

Descriptive Statistics

A study of the exploratory data process without drawing conclusions.

Inferential Statistics

A study of drawing conclusions about a population from a sample.

Relative Frequency

The frequency of a variable’s value over the total number of values for a variable.

Marginal Relative Frequency

The proportion of individuals with a specific value for a single categorical variable out of an entire sample’s total.

Joint Relative Frequency

The proportion of individuals with a specific value in two categorical variables out of a total sample. (AND)

Conditional Relative Frequency

The proportion of individuals that have a specific value of one variable among others in another categorical variable. (CONDITIONS)

Best Visual Distributions for One-Variable Categorical Data

Bar graphs, pie charts

Best Visual Distributions for Two-Variable Categorical Data

Side-by-side bar graph, segmented bar graph, mosaic plot

Best Visual Distributions for Discrete Quantitative Data

Dotplots, Stemplots

Shapes of Data

Symmetric, skewed left (left-tailed), skewed right (right-tailed), unimodal, bimodal

Variability of Data

Range, spacing between values