Transportation officials tell us that 90% of drivers wear seat belts while driving. What is the probability that between 525 and 530 drivers in a sample of 600 drivers wear seat belts?
A) 0.0811
B) 0.0174
C) 0.9015
D) 0.0985

Question

Quizplus · Accepted Answer

The problem can be solved using the normal approximation to the binomial distribution. The mean (μ) is np = 600 * 0.9 = 540, and the standard deviation (σ) is sqrt(np(1-p)) = sqrt(600 * 0.9 * 0.1) = 7.348. We find the z-scores for 524.5 and 530.5 (using continuity correction) and calculate the probability between these z-scores, which is approximately 0.0811.

Transportation Officials Tell Us That 90% of Drivers Wear Seat