AP Statistics · Topic 6.9
Justifying a Claim About the Difference of Two Proportions Practice
Part of Inference for Categorical Data: Proportions.(UNC-4.D)
Practice questions
2
Sample questions
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Sample 1difficulty 3/5
A 95% CI for p_A − p_B is (0.05, 0.20).
What can we conclude?
- A
p_A and p_B differ by exactly 0.125.
- B
No difference between groups.
- C
Convincing evidence p_A < p_B.
- Dcheck_circle
Convincing evidence p_A > p_B (since 0 is not in the CI).
Why
Both endpoints positive and 0 excluded, so we have evidence p_A > p_B.
- A
Sample 2difficulty 3/5
A 95% CI for p_A − p_B is (−0.02, 0.10).
What does the interval suggest about the difference in proportions?
- A
There is convincing evidence p_A < p_B.
- B
The proportions must be equal.
- Ccheck_circle
Since 0 is in the interval, no convincing evidence of a difference.
- D
There is convincing evidence p_A > p_B.
Why
A two-sample CI for the difference that contains 0 means we cannot conclude the proportions differ.
- A