Data on x = size of a house (in square feet) and y = amount of natural gas used (therms) during a specified period were used to fit the least squares regression line. The slope was 0.017 and the intercept was 25.0. Houses in this data set ranged in size from 1,000 to 3,000 square feet.
a. What is the equation of the least squares regression line?
b. What would you predict for gas usage for a 2,100 sq. ft. house?
c. What is the approximate change in gas usage associated with a 1 sq. ft. increase in size?
d. Would you use the least squares regression line to predict gas usage for a 500 sq. ft. house? Why or why not?