You are a manager of a company similar to Pella Corporation, a producer of high-quality doors and windows. The members of your marketing group give you the results of their research into the demand for your company’s doors. They report that the estimated coefficient for the effect of price on the demand for doors is -700 doors per dollar, with a standard error of 200 doors per dollar and a 95 percent confidence range of -1,092 doors per dollar to -308 doors per dollar.

a. Is the estimated coefficient significantly different from zero at the 95 percent confidence level? Explain your answer.

b. If you raise the price of a door by $10, what decrease in quantity do you expect?

Using the 95 percent confidence interval, what would be the largest decrease in quantity? The smallest?