A company's manufacturing process results in wastewater that contains an amount X (measured in parts per million) of a chemical pollutant. A "scrubbing" machine removes most of the chemical pollutant before pumping the wastewater into a nearby lake. The company must pay a large fine if the treated water contains more than 80 parts per million of the chemical pollutant, so the company sets the scrubbing machine to attain an expected chemical pollutant value E(X) = μ = 75 in the treated water. The distribution of chemical pollutant X in the treated water can be described by a normal model with expected value E(X) = 75 and standard deviation SD(X) = 4.2.