Herr Foods, a producer of a variety of salty snacks, would like to estimate the average weight of a bag of BBQ ­potato chips produced during the filling process at its Nottingham, Pennsylvania, plant. Determine the sample size needed to construct a 95% confidence interval with a margin of error equal to 0.005 ounces. Assume the standard deviation for the potato chip filling process is 0.02 ounces. Verify your result using PHStat.