Question 8 • Probability and Statistics with Applications Honors Sem-1-FL-1210300 (2024-2025)
Convert each response time to a z-score using z = (time − mean) ÷ standard deviation. For 4 minutes, z = (4 − 4.5) ÷ 1.2 ≈ −0.42; for 6 minutes, z = (6 − 4.5) ÷ 1.2 = 1.25. The area between these z-scores is about 0.8944 − 0.3372 = 0.5572, or 55.7%. The correct choice is 55.7%.
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