Question 872704
the mean of the commute time to work is 27.3min. assume that the standard deviation of the commute time is 18.1 min. to answer the following 
what  % of commuters in boston has a commute time within 2 standard deviations of the mean?
P(-2<= z <=2) = 0.9545 = 95.45%
-----------------------------------
Cheers,
Stan H.
------------