AP Statistics 1.1 - Analyzing Categorical Data

frequency

a count of an individual.

relative frequency

a ratio that compares the frequency of each category to the total.

proportion

a ratio that compares a number to 100 as a demical.

percent.

a ratio that compares a number to 100 as a percent.

bar graph

a graph that uses horizontal or vertical bars to display data; used to display the distribution of categorical data.

pie chart

a chart that shows the relationship of a part to a whole; used to display the distribution of categorical data.

two-way table

a table of counts that summarizes data on the relationship between two categorical variables for some group of individuals.

marginal relative frequency

gives the percent or proportion of individuals that have a specific value for one categorical variable.

joint relative frequency

gives the percent or proportion of individuals that have a specific value for one categorical variable and a specific value for another categorical variable.

conditional relative frequency

gives the percent or proportion of individuals that have a specific value for one categorical variable among individuals who share the same value of another categorical variable (the condition).

side-by-side bar graph

displays the distribution of a categorical variable for each value of another categorical variable. The bars are grouped together based on the values of one of the categorical variables and placed side by side.

segmented bar graph

displays the distribution of a categorical variable as segments of a rectangle, with the area of each segment proportional to the percent of individuals in the corresponding category.

association

between two variables if knowing the value of one variable helps us predict the value of the other.

no association

if knowing the value of one variable does not help us predict the value of the other.