ABSTRACT
Methyl tertbutyl ether is a volatile, flammable, colorless liquid manufactured by the chemical reaction of methanol and isobutylene. Methyl tertbutyl ether was first produced in the United States as a lead fuel additive in 1979 and then as an oxygenate in reformulated fuel in the 1990s. The confidence interval and testing procedures developed in earlier chapters all involve making inferences about population parameters. A host of nonparametric techniques are available for analyzing data that do not follow a normal distribution. Bacteria are a most important component of microbial ecosystems in sewage treatment plants. Water management engineers have determined that the percentages of active bacteria in sewage specimens collected at a particular plant have a distribution with a median of 40 percent. If the median percentage is larger than 40, then adjustments in the sewage treatment process must be made.
