Posted by Laura on Sunday, April 1, 2012 at 2:04pm.
If the grades on a police entrance exam are normally distributed with a mean of 100 and a standard deviation of 15, what percentage of students received grades of less than 115?

statistics  MathGuru, Monday, April 2, 2012 at 7:08pm
Use zscores.
z = (x  mean)/sd
x = 115
mean = 100
sd = 15
Use a ztable to find probability of less than 115 using the zscore calculated above. Convert to a percent.
I hope this will help.