Math
posted by nichole .
The mean of a set of normally distributed data is 550 and the standard deviation is 35.
What percent of the data is between 515 and 585?

Normalize 515 and 585, namely
z(515)=(515550)/35=1
z(585)=(585550)/35=1
The percent is the difference of probabilities of onetail zvalues between 1 and +1. It should be a little less than 70%.