2. Stacy owns a car that produces 100 horsepower. She is interested in understanding the relationship between gasoline consumption and power in cars. She has collected a random sample of 392 automobile models; each observation includes MPG (miles per gallon), and HP (horsepower). After concluding the relationship between these variables is non-linear, she focused on a regression of MP on sqrtHP (defined as the square root of HP i.e. ???). The output for that regression is provided in a separate sheet and labeled REGRESSION 1.

Question:Give a 99.7% confidence interval for the expected change of a car's MPG if the horsepower of the car increases by one HP unit. HINT: This is not a forecast & pay attention to the independent variables units

Dependent Variable: mpg Independent Variables: sqrtHP Equation: Predicted mpg = 58.705 - 3.504*sqrtHP R-Squared Adj.R-Sqr. Std.Err.Reg. Std.Dep.Var. # Fitted 0.644 0.643 4.665 7.805 392 Variable Coefficient Std.Err. t-Statistic P-value Constant 58.705 1.349 43.516 0.000 sqrtHP -3.504 0.132 -26.544 0.000 Forecast StErrFest sqrtHP 29.393 4.676 8.366600265 27.369 4.673 8.94427191 25.468 4.671 9.486832981 23.670 4.671 10 21.960 4.671 10.48808848 20.326 4.672 10.95445115 18.759 4.674 11.40175425