For Exercises 34–39, apply the Strategy for Building a Multiple Regression Model by performing the following steps, using level of significance :

  1. Step 1 Perform the test for significance of the overall regression.
  2. Step 2 Perform the tests for the individual predictors. If at least one of the predictors is not significant, then eliminate the variable with the largest -value from the model. Repeat Step 2 until all remaining predictors are significant.
  3. Step 3 Verify the assumptions.
  4. Step 4 Report and interpret your final model. Report and interpret the coefficients, the standard error of the estimate , and the adjusted coefficient of determination .

Question 13.138

vaweather

36. Virginia Weather. Table 8 contains data on weather in a sample of cities in the state of Virginia. We are interested in predicting .

Table 13.44: TABLE 8 Data on the weather in Virginia
City Heating
degreedays		 Avg.
Jan.
temp.		 Avg.
July
temp.		 Cooling
degreedays
Alexandria 4055 34.9 79.2 1531
Arlington 4055 34.9 79.2 1531
Blacksburg 5559 30.9 71.1 533
Charlottesville 4103 35.5 76.9 1212
Chesapeake 3368 40.1 79.1 1612
Danville 3970 36.6 78.8 1418
Hampton 3535 39.4 78.5 1432
Harrisonburg 5333 30.5 73.5 758
Leesburg 5031 31.5 75.2 911
Lynchburg 4354 34.5 75.1 1075
Manassas 4925 31.7 75.7 1075
Newport News 3179 41.2 80.3 1682
Norfolk 3368 40.1 79.1 1612
Petersburg 3334 39.7 79.6 1619
Portsmouth 3368 40.1 79.1 1612
Richmond 3919 36.4 77.9 1435
Roanoke 4284 35.8 76.2 1134
Suffolk 3467 39.6 78.5 1427
Virginia Beach 3336 40.7 78.8 1482
Table 13.44: Source: National Oceanic and Atmospheric Administration.