Chapter 1.1 AP Statistics Vocab

Statistics

is the science and art of collecting, analyzing, and drawing conclusions from data.

Individuals

is an object described in a set of data. Can be people, animals, or things

Variable

is an attribute that can take different values for different individuals.

Categorical variable

assigns labels that place each individual into a particular group, called a category

Quantitative variable

takes number values that are quantities, counts or measurements.

Discrete variable

A quantitative variable that takes a fixed set of possible values with gaps between them

Continuous variable 

A quantitative variable that can take any value in an interval on the number line

Distribution

tells us what values the variable takes and how often it takes those values

Frequency Table

shows the number of individuals having each value

Relative frequency table

table shows the proportion or percent of individuals having each value

Bar Graph

shows each category as a bar. The heights of the bars show the category frequencies or relative frequencies.

Pie Chart 

shows each category as a slice of the “pie".” The areas of the slice are proportional to the category frequencies or relative frequencies.

Two-way table

is 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. 

Mosaic Plot 

is a modified segmented bar graph in which the width of each rectangle is proportional to the number 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. If knowing the value of one variable does not help us predict the value of the other, then there is no association between the variables.