AP Statistics Linear Regression

Front

What should a residual plot look like?

Back

Random with no pattern.

Front

Which statement is TRUE regarding residuals and correlation? I. Random scatter in the residuals indicates a linear model. II. If two variables are very strongly associated, then the correlation between them will be near 1 or -1. III. Changing the units of measurement for x or y changes the correlation coefficient.

Back

I and II only.

Front

Estimate the correlation coefficient for a strong negative association.

Back

r ≈ -0.8.

Front

What does the slope of a linear regression indicate in the context of caffeine intake and study time?

Back

For each additional 1 mg of caffeine, the study time is predicted to increase by 0.164 hours.

Front

Using the formula y = -60x + 6443, what are the coffee sales on a 34° day?

Back

$4403.

Front

Define 'linear regression'.

Back

A statistical method used to model the relationship between a dependent variable and one or more independent variables by fitting a linear equation.

Front

What is a residual in linear regression?

Back

The difference between the observed value and the predicted value from a regression model.

Front

What does a random residual plot indicate?

Back

It suggests that a linear model is appropriate for the data.

Front

What is the correlation coefficient?

Back

A numerical measure of the strength and direction of the linear relationship between two variables, ranging from -1 to 1.

Front

What does a correlation coefficient of r = 1 indicate?

Back

A perfect positive linear relationship between two variables.