A health reporter wants to estimate the proportion of adults aged 18 to 75 in her state who exercise at least three times a week. She plans to post a link to an online survey on social media and use the responses of everyone who completes it. Which of the following is the most important reason that her estimate is likely to be biased?
random sampling and data collection
Review random sampling and data collection for AP Statistics and try 2 free AP-style practice questions. 17 questions on this topic in AP Statistics · Unit 3 · Collecting Data.
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A psychologist studying the mental health of college students first selects 20 universities at random, then selects 5 dormitories at random within each selected university, and finally selects 10 students at random within each selected dormitory. Which of the following best describes this sampling method?
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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."