[EX06-063] The data are the net weights (in grams) for a sample of 30 bags of M&M’s. The advertised net weight is 47.9 grams per bag.

46.22 46.72 46.94 47.61 47.67 47.70 47.98 48.28 48.33 48.45 48.49 48.72 48.74 48.95 48.98 49.16 49.40 49.69 49.79 49.80 49.80 50.01 50.23 50.40 50.43 50.97 51.53 51.68 51.71 52.06 Source: http://www.math.uah.edu/stat/, Christine Nickel and Jason York, ST 687 project, fall 1998 The FDA requires that (nearly) every bag contain the advertised weight; otherwise, violations (less than 47.9 grams per bag) will bring about mandated fines. (M&M’s are manufactured and distributed by Mars Inc.)

a. What percentage of the bags in the sample are in violation?

b. If the weight of all filled bags is normally distributed with a mean weight of 47.9 g, what percentage of the bags will be in violation?

c. Assuming the bag weights are normally distributed with a standard deviation of 1.5 g, what mean value would leave 5% of the weights below 47.9 g?

d. Assuming the bag weights are normally distributed with a standard deviation of 1.0 g, what mean value would leave 5% of the weights below 47.9 g?

e. Assuming the bag weights are normally distributed with a standard deviation of 1.5 g, what mean value would leave 1% of the weights below 47.9 g?

f. Why is it important for Mars to keep the percentage of violations low?

g. It is important for Mars to keep the standard deviation as small as possible so that in turn the mean can be as small as possible to maintain net weight. Explain the relationship between the standard deviation and the mean.

Explain why this is important to Mars.