AP Stats Unit 2

What can you conclude from this graph?

• The least squares regression equation overestimates y more often than it underestimates y.

• This is a good model. because all of the residuals are close to the line y=0.

• When x = 5, the least squares regression equation underestimates y.

Find the equation of the least-squares regression line.
Round your entries to the nearest hundredth. Use y^ for y-hat.

What effect(s) would removing this point have?

Choose all answers that apply:

• The correlation coefficient (r) would get closer to -1.

• The standard deviation of the residuals would increase.

• The y-intercept would increase.

• No change.

Liz's math test included a survey question asking how many hours students spent studying for the test. The scatterplot and regression line show the relationship between how many hours students spent studying and their score on the test. The fitted line has a slope of 15. What is the best interpretation of this slope?

• The model predicts that students who scored 0 studied for an average of 15 hours.

• The model predicts that students who didn't study at all will have an average score of 15 points.

• The model predicts that the score will increase 15 points for each additional hour of study time.

• The model predicts that the study time will increase 15 hours for each additional point scored.

Which of these is an appropriate least-squares equation for this model?

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Look at the image to see the question & answer choices.

• A

• B

• C

Interpret the residual for the bunch indicated in the scatterplot above.

• This bunch's storage temperature was 2*C warmer than predicted based on the storage life.

• This bunch's storage temperature was 2*C cooler than predicted based on the storage life.

• This bunch's storage temperature was 2 days longer than predicted based on the storage temperature.

• This bunch's storage temperature was 2 days fewer than predicted based on the storage temperature.

What is the first mistake in Allie's response?

• Point A is not an outlier.

• Removing this point would strengthen the overall pattern, not weaken it.

• Removing this point would get r closer to -1, not to 0.

• Removing this point would get r closer to 1, not to 0.

Choose the best display.

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What, if anything, is missing from this description?

• Form

• Direction

• Strength

• Outliers