The number of chocolate chips in a bag of chocolate chip cookies is approximately normally distributed with a mean of 1264 chips and a standard deviation of 116 chips. (a) Determine the 28th percentile for the number of chocolate chips in a bag. (b) Determine the number of chocolate chips in a bag that make up the middle 96% of bag.

Answer 1

This might help:
http://davidmlane.com/hyperstat/z_table.html