Farmed salmon is much cheaper to bring to market than salmon caught in the wild, but consumers are concerned about several issues recently publicized about farmed salmon, including the type of food they are fed and the contaminants found in their meat (see www.healthcastle.com). Among the contaminants are such compounds as polychlorinated biphenyls (PCBs), dioxins, toxaphene, dieldrin, hexachlorobenzene, lindane, heptachlor epoxide, cis-nonachlor, trans-nonachlor, gammachlordane, alpha-chlordane, Mirex, endrin, and DDT.

The EPA recommends that salmon contain no more than 0.08 ppm of the insecticide Mirex. A local environmental group is considering a boycott of salmon if it exceeds 0.08 ppm. A 95% confidence interval based on a sample of farmed salmon from a random sample of 150 different salmon farms (Source: Science, 9, January 2004) is found to be 0.0834 to 0.0992 ppm. The data were unimodal and symmetric, with no outliers.

a) Is there evidence that the farms are producing salmon with mean Mirex contamination higher than the EPA recommended amount? Your explanation should discuss the confidence level, the P-value, and the decision.

b) Discuss the two types of errors that can be made in the context of a business decision of whether to prohibit the producers from selling their salmon.