Representing a Categorical Variable with Tables - AP Statistics

1. Sum all values: $3 + 7 + 10 = 20$.

1. Add frequencies progressively: $2 + 3 + 5 = 10$.

Color of a car. Car color sorts objects into distinct groups like red, blue, green.

A variable that describes categories or groups. These variables classify data into distinct groups rather than measuring quantities.

By focusing on a row or column's data. Fix one variable and examine how the other varies within that subset.

Marginal totals. These show the overall frequency for each level of one variable.

Frequency table. Simple frequency tables display one variable's category counts.

$0.25$. Divide count by total: $\frac{15}{60} = 0.25$.

The total number of observations. The grand total represents the entire sample size.

To find the total counts for each variable. Marginal totals show the overall distribution of each variable separately.

Another name for a two-way table. Cross-tabulation and two-way tables are identical concepts.

20%. Convert to percentage: $\frac{5}{25} \times 100% = 20%$.

Rows, columns, and cells. Rows show one variable's categories, columns show the other's, cells show counts.

No observations for that category combination. Zero means no cases have that particular combination of characteristics.

$0.2$. Divide count by total: $\frac{9}{45} = 0.2$.

Cumulative frequency table. Displays running totals that accumulate through ordered categories.

Two-way table. Two-way tables cross-classify observations by two categorical variables.

The relationship between two categorical variables. Shows patterns of association between two categorical variables.

A category with its frequency. Each row displays one category and its corresponding count.

Distribution of one variable given a specific condition. Shows how one variable behaves when the other is held constant.

Another name for a two-way table. Both terms describe tables organizing data by two categorical variables.

Categorical variables. Tables organize categorical data into countable groups or categories.

1. Add all individual counts: $5 + 10 + 15 = 30$.

$0.2$. Divide count by total: $\frac{8}{40} = 0.2$.

Relative frequency table. Converts raw counts to proportions of the total sample.

A table showing percentages for each category. Multiplies relative frequencies by 100 to show data as percentages.

A count for a specific combination of categories. Each cell shows how many observations have that row-column combination.

Frequency is count; relative frequency is proportion. Frequency counts observations; relative frequency shows their proportion.

1. Sum the counts: $4 + 6 + 10 = 20$.