A manufacturer of chocolate candy makes a variety of chocolate bars, including a 12-ounce chocolate bar (340 grams). Specifications for the 12-ounce bar are 330 grams and 350 grams. A recent sample from the production process results in bars with an average net weight of 342grams with a standard deviation of 2.8 grams.

a. Compute the capability ratio Cp

b. Compute the capability index Cpk

c. Is this process capable? Explain.

d. What is the largest standard deviation (in grams) that the machine that fills the bar molds can have and still be considered capable (at the 4-sigma level) if the average fill is 340 grams?