Regression and Residuals

What should a residual plot look like?

• Distinct Pattern

• Curve

• Random

Shown is a residual plot. Would a linear regression model of the data be most appropriate?

• YES

• NO

Shown is a residual plot. How many positive residuals are there?

• 5

• 1

• 3

• 9

• This residual plot represents a linear fit.
• This residual plot represents a nonlinear fit.
• This residual plot represents no fit.

If the point with the red x is removed from the scatterplot, what will happen to the slope of the LSRL and the correlation coefficient?

• slope increases, r increases

• slope decreases, r increases

• slope increases, r decreases

• slope decreases, r decreases

• slope is unchanged, r increases

What is the value of the correlation coefficient?

• 0.891

• -0.891

• 0.875

• 0.943

• -0.943

The residual plots from five different least squares regression lines are shown below. Which of the plots shows the strongest evidence that its regression line is an appropriate model for the data and is consistent with the assumptions required for inference for regression?

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• 
• 
• 
• 

Which of these points appears to be an “Outlier?”

• A

• B

• C

• D

If the line of regression is y = 3.45x - 6.7 and the actual point is (5,12), what is the residual for that point?

• 1.45

• -1.45

• 34.7

• -34.7

What is a line of best fit used for?

• To make predictions

• To make the graph look pretty

• To connect the points