Running times for 400 meters are Normally distributed for young men between 18 and 30 years of age, with a mean of 93 seconds and a standard deviation of 16 seconds. Thus, 99.7% of running times are approximately between:
A)45 and 141 seconds.
B)61 and 125 seconds.
C)77 and 109 seconds.
D)None of the answer options is correct.

Question

Quizplus · Accepted Answer

The 99.7% range for a normal distribution is defined by the mean plus or minus three standard deviations. Here, with a mean of 93 seconds and a standard deviation of 16 seconds, the range is 93 ± (3*16) = 93 ± 48, which gives us 45 seconds to 141 seconds.

Running Times for 400 Meters Are Normally Distributed for Young