Answer:
C. 45 and 141 seconds
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 93 seconds
Standard deviation = 16 seconds
99.7% of running times are approximately between:
By the Empirical rule, within 3 standard deviations of the mean, so between 3 standard deviations below the mean and 3 standard deviations above the mean
3 stnadard deviations below the mean
93 - 3*16 = 45 seconds
3 standard deviations above the mean
93 + 3*16 = 141 seconds
The correct answer is:
C. 45 and 141 seconds
