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.Because a fine is charged if regulations are not met, the Company sets the machine to attain an average of 75 ppm in the treated water.The Machine's output can be described by a normal model with standard deviation 4.2 ppm.What Percent of the batches of water discharged exceed the 80 ppm standard?

Question

Quizplus · Accepted Answer

Using the normal distribution, we calculate the z-score for 80 ppm: z = (80 - 75) / 4.2 ≈ 1.19. The percentage of batches exceeding 80 ppm corresponds to the area to the right of this z-score, which is approximately 11.7%.

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