AP Statistics · Topic 2.6
Linear Regression Models Practice
Part of Exploring Two-Variable Data.(DAT-1.C)
Practice questions
17
Sample questions
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Sample 1difficulty 2/5
The regression predicts MPG from weight (in 1000 lb units).
Interpret the slope -6.0.
- A
For each additional MPG, weight decreases by 6
- Bcheck_circle
For each additional 1000 lb, predicted MPG decreases by 6
- C
MPG decreases by 6% per pound
- D
Heavier cars get 6 MPG
Why
Slope is the predicted change in MPG (y) per one-unit (1000 lb) increase in x.
- A
Sample 2difficulty 2/5
A regression predicts highway MPG from car weight in thousands of pounds.
Predict MPG for a car weighing 3,000 lb.
- A
39
- Bcheck_circle
27
- C
21
- D
33
Why
y-hat = 45 - 6.0(3.0) = 45 - 18 = 27 MPG.
- A
Sample 3difficulty 2/5
A regression predicts weight from height.
The intercept -120 lb is best described as:
- A
The predicted weight when x = 60 inches
- B
The slope of the line
- Ccheck_circle
Not meaningful in context because height = 0 is far outside the data range
- D
The mean weight in the sample
Why
Extrapolating to x = 0 (zero inches tall) lies outside the observed range, so the intercept has no real-world meaning here.
- A
Sample 4difficulty 2/5
For a least-squares regression, x-bar = 10 and y-bar = 25.
What does the line predict at x = 10?
- A
0
- B
10
- C
Cannot be determined
- Dcheck_circle
25
Why
The least-squares line passes through (x-bar, y-bar), so it predicts y-bar at x-bar.
- A
Sample 5difficulty 2/5
The y-intercept a in ŷ = a + bx is
- A
Always 0
- B
Slope of line
- C
Mean of x
- Dcheck_circle
Predicted y when x = 0
Why
Intercept = predicted y at x = 0 (interpret cautiously if x = 0 is far from data).
- A