Georgia-Pacific is a major forest products company in the United States. In addition to timberlands, the company owns and operates numerous manufacturing plants that make lumber and paper products. At one of their plywood plants, the operations manager has been struggling to make sure that the plywood thickness meets quality standards. Specifically, all sheets of their 3/4-inch plywood must fall within the range 0.747 to 0.753 inches in thickness. Studies have shown that the current process produces plywood that has thicknesses that are normally distributed with a mean of 0.751 inches and a standard deviation equal to 0.004 inches.
a. Use Excel to determine the proportion of plywood sheets that will meet quality specifications (0.747 to 0.753), given how the current process is performing.
b. Referring to part a, suppose the manager is unhappy with the proportion of product meeting specifications. Assuming that he can get the mean adjusted to 0.75 inches, what must the standard deviation be if he is going to have 98% of his product meet specifications?