SOLUTION: The time it takes for high school boys to run 1 mile is normally distributed with a mean of 460 seconds and a
standard deviation of 40 seconds. All those falling in the slowest 20
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Question 1172516: The time it takes for high school boys to run 1 mile is normally distributed with a mean of 460 seconds and a
standard deviation of 40 seconds. All those falling in the slowest 20 percent are deemed to need additional
training. What is the critical time above which one is deemed to need additional training?
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
z for the slowest 20% is z=0.8416
z is positive because the time will be longer than the mean, given we are looking for slower runners.
z=(x-mean)/sd
0.8416=(x-460)/40
x=493.66 seconds or 494 seconds.
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