AP®︎ Statistics: Topic 5.2 Flashcards

Master key terms and definitions for Topic 5.2 of AP Statistics – Correlation to help you prep for quizzes and the AP exam.

0%
17 cards total
17 not started
0 learning
0 almost done
0 mastered
Term

Correlation Coefficient (r)

Definition

Numerical summary of the direction and strength of the linear association between two quantitative variables

1 / 17
Correlation Coefficient (r)
Not Started

Numerical summary of the direction and strength of the linear association between two quantitative variables

5.2.A5.2.A.1
Positive Linear Association
Not Started

As one variable increases, the other tends to increase; shown by r > 0

5.2.A5.2.A.1
Negative Linear Association
Not Started

As one variable increases, the other tends to decrease; shown by r < 0

5.2.A5.2.A.1
No Linear Association
Not Started

r = 0; no linear association between two quantitative variables

5.2.A5.2.A.2
Strength of Linear Association
Not Started

Determined by |r|: values near 1 mean strong linear association, values near 0 mean weak linear association

5.2.A5.2.A.2
Perfect Positive Linear Association
Not Started

r = 1; all points lie exactly on a nonhorizontal straight line with positive slope

5.2.A5.2.A.2
Perfect Negative Linear Association
Not Started

r = -1; all points lie exactly on a nonhorizontal straight line with negative slope

5.2.A5.2.A.2
Correlation Measures Only Linear Association
Not Started

Correlation describes only linear association: a strong nonlinear relationship can have r = 0, and a large |r| does not by itself mean a linear model is appropriate

5.2.A5.2.A.3
Scatterplot Before Correlation
Not Started

Always examine the scatterplot before interpreting r because r does not show curvature, clusters, gaps, or unusual observations

5.2.A5.2.A.3
Unit-Free
Not Started

Correlation has no units because it is based on standardized values; changing measurement units does not change r

5.2.A5.2.A.1
Symmetry of Correlation
Not Started

The correlation between x and y is the same as the correlation between y and x

5.2.A
Not Resistant
Not Started

Correlation is not resistant; an unusual observation can greatly change the sign and size of r

5.2.A
Influential Point
Not Started

An unusual observation whose location has a large effect on a numerical summary such as r

5.2.A
Correlation Does Not Imply Causation
Not Started

An association between two variables does not by itself show that changes in one cause changes in the other

5.2.A5.2.A.4
Lurking Variable
Not Started

A third variable associated with both measured variables that may help explain their relationship

5.2.A5.2.A.4
Confounding
Not Started

When the effects of a lurking variable cannot be separated from the effects of an explanatory variable

5.2.A5.2.A.4
Undefined Correlation
Not Started

Correlation is undefined if either variable has standard deviation 0; if all x-values or all y-values are the same, r cannot be computed

5.2.A