SOLUTION: Use the 68-95-99.7 rule to solve the problem. For women at Hartford College, times to run 400 meters are normally distributed with a mean of 82 seconds and a standard deviation

Question 1084226: Use the 68-95-99.7 rule to solve the problem.
For women at Hartford College, times to run 400 meters are normally distributed with a mean of 82 seconds
and a standard deviation of 7 seconds. What percentage of the times are more than 68 seconds?
A) 5%
B) 95%
C) 2.5%
D) 97.5%
Answer by rothauserc(4718) (Show Source): You can put this solution on YOUR website!
82 - 68 = 14 seconds which is two standard deviations below the mean
:
the 95% rule says that 95% of the observed means will fall within two standard deviations above and below the mean
:
therefore 5% are above and below the mean and we need 0.05 / 2 = 0.025
:
The percentage of the times that are more than 68 seconds = 1 - 0.025 = 97.5%
:
answer is D.
:

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