A producer of variety of salty snacks would like to estimate

A producer of variety of salty snacks would like to estimate the average weight of a bag of BBQ potato chips produced during the filling process at one of its plants. Determine the sample size needed to construct a 99% confidence interval with a margin of error equal to 0.005 ounces. Assume the standard deviation for the potato chip filling process is 0.03 ounces.

The sample size needed is _____ ?
(Round up to the nearest integer.)

Solution

A producer of variety of salty snacks would like to estimate the average weight of a bag of BBQ potato chips produced during the filling process at one of its plants. Determine the sample size needed to construct a 99% confidence interval with a margin of error equal to 0.005 ounces. Assume the standard deviation for the potato chip filling process is 0.03 ounces.

For 99%, z=2.576

d=0.005

sd=0.03

Sample size = (z²*s²)/d²

= (2.576²*0.03²)/0.005²

=238.88

The sample size required= 239