Mean annual temperatures for two California cities. Table 28.11 contains data on the mean annual temperatures (degrees Fahrenheit) for the years 1951 to 2005 at two locations in California: Pasadena and Redding.13
(a) Plot the temperatures versus year using different symbols for the two cities.
(b) Would you be willing to use a multiple regression model with parallel slopes to predict temperatures from year for the two different cities? Explain.
(c) Fit a model that will allow you to test the hypothesis that the slope of the regression line for Pasadena is equal to the slope of the regression line for Redding. Conduct the test for equal slopes.
(d) Are the conditions for inference met for your model in part (c)? Construct appropriate residual plots and comment.