Chapter 1 AP Stats Vocab

WE GOT THISSSS

Individuals

the objects described by a set of data. May be people, animals, or things

Variable

any characteristic of an individual. Can take different values for different individuals

Categorical variable

places individuals into groups or categories based on a characteristic. Ex: Eye color (blue, brown, green, ect)

Quantitative variable

takes numerical values representing a measurable quantity, where arithmetic makes sense. Ex: a student’s height ( 65 inches )

Distribution

Describes the values a variable takes and how often those values occur. Ex: A distribution of students’ test scores might show that most students scored between 80 and 90.

What graphs can display the distribution of a categorical variable?

A pie chart or bar graph can display the distribution of a categorical variable. Ex: A bar graph showing how many students prefer cats, dogs, or birds.

Marginal distribution

The distribution of one categorical variable in a two-way table, ignoring the other variable.

Conditional distribution

The distribution of one variable for a specific value or category of another variable. Ex: The percentage of males who prefer basketball, soccer, or football.

Association

A relationship between two variables where knowing the value of one variable gives you information about the other. Ex: If students who study more hours tend to have higher test scores, there is an association between study time and test score.

Dotplot

A graph that displays the distribution of a quantitative variable using dots above a number line. Each dot represents one observation

Symmetric Distribution

A distribution where the left and right sides have approximately the same shape and spread.

Skewed Distribution

A distribution that is not symmetric because one side has a longer tail than the other

Stemplot (Stem-and-Leaf Plot)

A graph that organizes quantitative data by separating each value into a stem and a leaf while keeping the original data values.

Histogram

A graph that displays the distribution of a quantitative variable by grouping values into intervals (bins) and using bars to show the frequency.

Mean

The average of a set of quantitative data. Add all the values together and divide by the number of values.

Median

The middle value of a data set when the values are arranged in order. If there are two middle values, take their average.

Five-Number Summary

A summary of a quantitative data set using five values: the minimum, first quartile (Q1), median, third quartile (Q3), and maximum.