Fuel Economy. For Exercises 60–67, refer to the table of fuel economy data from Exercises 80–84 in Section 4.2. The predictor variable is , expressed in liters; the response variable is , expressed in miles per gallon (mpg).

Question 4.264

63. Correlation. Do the following:

  1. Use and to find the correlation coefficient, .
  2. Interpret the correlation between engine size and combined mpg.

4.3.63

(a) (b) This value of is very close to the minimum value . We would therefore say that the gas mileage and the engine displacement are negatively correlated. As the engine displacement of a car increases, the gas mileage of the car tends to decrease.