Refer to the demand for cell phones regression given in Eq. (3.7.3).

Eq (3.7.3)

a. Is the estimated intercept coefficient significant at the 5 percent level of significance? What is the null hypothesis you are testing?

b. Is the estimated slope coefficient significant at the 5 percent level? What is the underlying null hypothesis?
c. Establish a 95 percent confidence for the true slope coefficient.
d. What is the mean forecast value of cell phones demanded if the per capita income is $9,000? What is the 95 percent confidence interval for the forecast value?

Y; = 14.4773 + 0.0022X;