4. Cellulon, a manufacturer of home insulation, wants to develop guidelines for builders and consumers on how the thickness of the insulation in the attic of a home and the outdoor temperature affect natural gas consumption. In the laboratory it varied the insulation thickness and temperature. A few of the findings are:

On the basis of the sample results, the regression equation is:

a. How much natural gas can homeowners expect to use per month if they install 6 inches of insulation and the outdoor temperature is 40 degrees F?

b. What effect would installing 7 inches of insulation instead of 6 have on the monthly natural gas consumption (assuming the outdoor temperature remains at 40 degrees F)?

c. Why are the regression coefficients b1 and b2 negative? Is this logical?

Transcribed Image Text:

Monthly Natural Gas Consumption Thickness of Insulation (cubic feet), Y (inches), X Outdoor Temperature (F), X2 30.3 6 40 26.9 12 40 22.1 8 49