A Company's Manufacturing Process Uses 500 Gallons of Water at a Time.A

Multiple Choice

A company's manufacturing process uses 500 gallons of water at a time.A "scrubbing" machine then removes most of a chemical pollutant before pumping the water into a nearby
Lake.To meet federal regulations the treated water must not contain more than 80 parts per
Million (ppm.) of the chemical.The machine's output can be described by a normal model
With standard deviation 4.2 ppm.The company's lawyers insist that not more than 2% of the
Treated water should be over the limit.To achieve this, to what mean should the company set
The scrubbing machine?

A) 80 ppm.
B) 75 ppm.
C) 71.374 ppm.
D) 88.626 ppm.
E) 69.459 ppm.