A physical fitness association is including the mile run in its secondary-school fitness test. The time for thisevent for boys in secondary school is known to possess a normal distribution with a mean of 460 seconds and astandard deviation of 60 seconds. Between what times do we expect most (approximately 95%) of the boys torun the mile?
A) between 342.4 and 577.6 sec
B) between 361.3 and 558.736 sec
C) between 365 and 555 sec
D) between 0 and 558.736 sec

Question

Quizplus · Accepted Answer

To find the range where approximately 95% of the boys' mile run times fall, we use the 95% confidence interval for a normal distribution, which is mean ± 1.96(standard deviation). Thus, 460 ± 1.96(60) = 460 ± 117.6 = [342.4, 577.6] seconds.

A Physical Fitness Association Is Including the Mile Run in Its