Finding the probability value for the given data using normal approximation
A study of the amount of time it takes a mechanic to rebuild transmission for a 1992 Chevrolet Cavalier shows that the mean is 8.4 hours and the standard deviation is 1.8 hour. If 40 mechanics are at random selected, find the possibility that their mean rebuild time exceeds 9.1 hours.
a.0.1285
b.0.0046
c.0.0069
d.0.1046