The number of kernels of corn in a bag of microwave popcorn

The number of kernels of corn in a bag of microwave popcorn is 1262 kernels wtih a standard deviation of 118 kernels. Determine the 30^th percentile for the number of kernels in a bag of microwave popcorn.

Solution

First subtract 0.30 from 1

That is 1-0.30=0.7

The z score closest to 0.7 is: 0.53

The X score is: +z=1262+0.53*118=1324.54

Thus, the 30^th percentile for the number of kernels in a bag of microwave popcorn is 1324.54