Suppose the average wind speed equals 12 miles per hour, and that wind speeds are normally distributed. the standard deviation is 3.4 miles per hour. Find the probability that the wind speed will exceed 13.5 miles per hour.

( I am using a TI-83plus)

This is what I am thinking...

Normalcdf(.10, 13.5, 12, 3.4) = .67 or 67%

I have already been told this is not right! I am not looking for the correct answer on a silver platter. Just looking for directions in solving this. Pleeez!