The EPA is concerned about the quality of drinking water served on airline flights. In September 2004, a sample of 158 flights found unacceptable bacterial contamination on 20 flights. (a) At α = .05,...

The EPA is concerned about the quality of drinking water served on airline flights. In September 2004, a sample of 158 flights found unacceptable bacterial contamination on 20 flights. (a) At α = .05, does this sample show that more than 10 percent of all flights have contaminated water? (b) Find the p-value. (Data are from The Wall Street Journal, November 10, 2004, p. D1.)