Review confidence intervals for the slope of a regression model for AP Statistics and try 1 free AP-style practice question. 14 questions on this topic in AP Statistics · Unit 9 · Inference for Quantitative Data: Slopes.
A school district analyst regressed exam score on hours of study for a random sample of 30 students. The output is shown.
| Variable | Coeff | SE Coeff | t | P |
|---|---|---|---|---|
| Constant | 52.1 | 4.3 | 12.12 | 0.000 |
| Study hours | 3.84 | 1.12 | 3.43 | 0.002 |
The residual standard deviation is 8.6 with 28 degrees of freedom. Using the critical value 2.048, which of the following is a 95 percent confidence interval for the slope of the population regression line?
Full practice for AP Statistics · Unit 9 · Inference for Quantitative Data: Slopes: timed tests, step-by-step explanations for every answer, and AI grading for free-response questions.
Start practicing freeAnswer, then see why
The price of gasoline rises 10% and the quantity demanded falls 5%. What happens to total revenue?
Not quite. The answer is B.
Why the other options are wrong
AI grading for free-response
Write your FRQ answer and get it scored point by point against the AP rubric, with the line from your answer that earned or missed each point.
Reason: Correctly identifies demand for gasoline as inelastic.
Evidence: "The price of gasoline rises and the quantity falls only a little."
Reason: Graph shows relatively inelastic demand.
Evidence: Draws a steep demand curve.
Reason: Correct new equilibrium price.
Evidence: Shifts supply left, P1 → P2.
Reason: With inelastic demand, a price increase raises total revenue.
Evidence: "Revenue goes down."