A student wants to perform a significance test to compare the proportion of two independent random samples who support a proposed zoning change: 14 of 60 residents in Neighborhood 1 and 9 of 55 residents in Neighborhood 2. Before performing the test, the student must check the large counts condition using the pooled proportion, which is . Which of the following correctly evaluates this condition?
inference for the difference of two proportions
Review inference for the difference of two proportions for AP Statistics and try 2 free AP-style practice questions. 19 questions on this topic in AP Statistics · Unit 6 · Inference for Categorical Data: Proportions.
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A factory operates two production lines that use different machinery to assemble the same product. A quality control manager took independent random samples of items from each line and performed a two-proportion z-test comparing the proportion of defective items produced by each line. The test produced a p-value of 0.018, and the manager wants to explain to the plant supervisor exactly what this p-value represents. Which of the following is a correct interpretation?
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Answer, 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.
Question 13 / 4 pts
Part a1 / 1 pts
Point 1: Earned
Grader confidence 94% sureReason: Correctly identifies demand for gasoline as inelastic.
Evidence: "The price of gasoline rises and the quantity falls only a little."
Part b2 / 3 pts
Point 1: Earned
Grader confidence 91% sureReason: Graph shows relatively inelastic demand.
Evidence: Draws a steep demand curve.
Point 2: Earned
Grader confidence 88% sureReason: Correct new equilibrium price.
Evidence: Shifts supply left, P1 → P2.
Point 3: Not earned
Grader confidence 82% sureReason: With inelastic demand, a price increase raises total revenue.
Evidence: "Revenue goes down."