Question 9 • AQR_A_IC
The sample proportion is 273/300 = 0.91. Under the claim p = 0.95, the standard error is √(0.95 × 0.05/300) ≈ 0.0126, so z = (0.91 − 0.95)/0.0126 ≈ −3.18. Because the alternative is that the true proportion is less than 95%, use the lower-tail probability; for z = −3.18, the P-value is about 0.0007. Thus, the correct choice is z = −3.18 and P-value = 0.0007.
AI-written and checked against the verified answer.