The Golden Snow Globe website shows that four U.S. cities with a population of at least 100,000 (Rochester, NY; Salt Lake City, UT; Madison, WI; Bridgeport, CT) had recorded between 60 and 70 inches of snow for the winter of 2012–13 as of the evening of March 9, 2013 (Golden Snow Globe website, March 13, 2013). Such large amounts of snowfall can make the local roads difficult to negotiate. Is there a difference in how well these four cities keep streets clear of snow? A sample of truck drivers who drive in each of these four cities was taken, and the drivers were asked whether the city does a satisfactory job in keeping its streets clear of snow. The results of these samples follow.

a. Use the sample data to calculate the point estimate of the population proportion of truck drivers who rated each of these cities as satisfactory in keeping its streets clear of snow.
b. Conduct a hypothesis test to determine if the population proportion of truck drivers who rate whether the city does a satisfactory job of keeping its streets clear of snow is equal for these four cities. Using a .05 level of significance, what is the p-value and what is yourconclusion?

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Rochester, NY 27 21 Salt Lake City, UT Satisfactory Not Satisfactory Madison, WI 29 18 Bridgeport, CT 24 21 35 21