SOLUTION: Suppose commute times in a large city are normally distributed and that 62.50% of commuters in this city take more than 20 minutes to commute one-way. If the standard deviation of

SOLUTION: Suppose commute times in a large city are normally distributed and that 62.50% of commuters in this city take more than 20 minutes to commute one-way. If the standard deviation of

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Question 1195825: Suppose commute times in a large city are normally distributed and that 62.50% of commuters in this city take more than 20 minutes to commute one-way. If the standard deviation of such commutes is 6.5 minutes, what is the mean commute?
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
z(x)=0.6450
z=+0.319
z=(x-mean)/sd
0.319=(x-20)/6.5
x-20=2.07
x=22.07 min. That is the mean time.
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