Let x be the size of a house (in square feet) and y be the amount of natural gas used (therms) during a specified period. Suppose that for a particular community, x and y are related according to the simple linear regression model with the following values. B a slope of population regression line = 0.012 y intercept of population regression line = 6 Houses in this community range in size from 1,000 to 3,000 square feet. (a) What is the equation of the population regression line