AP Statistics Chapter 3 - Examining Relationships

Correlation

________ measures the strength of a linear relationship between two variables, not curved relationships.

overall pattern

A deviation from the ________ of a scatterplot is called an outlier.

 Strength

________ can be described as weak, moderate or strong.

quantitative variables

Correlation Correlation measures the strength and direction of the relationship between two ________.

Positive r

________ indicates a positive association between x and y.

clear explanatory response

If there is no ________ relationship between the two variables, then either variable can be placed on either axis.

Correlation

________ is only calculated for quantitative variables, not categorical.

Correlation

________ is always a number between- 1 and +1.

correlation

When calculating ________, it makes no difference which variable is x and which is y.

Correlation

________ is usually represented by the letter r. Facts about ________ 1.

3.2

Least-Squares Regression Regression Line A regression line is a straight line that describes how a response variable y changes as an explanatory variable x changes

The residual plot is used to determine whether a linear equation is a good model for a set of data, as follows

 If the residual plot exhibits randomness, then a line is a good model for the data (see left)  If the residual plot exhibits a pattern, then a line is NOT a good model for the data (right)