Your company manufactures miniature agricultural structures with uplifting messages printed on them, for sale in bookstores ("Barns Ennoble"). You've collected data on annual sales (S, number of toy barns sold per year) the price of your toy barn (P, in dollars), and the population size in the different cities in which your company has retail locations (N, number of people; you currently only have one establishment in each city). You estimate the following regression model: S = a + bP + cN. In your regressions, you usually look for a 10%-or-better level of confidence.

a. What signs do you expect for a, b, and c?

b. Your regression yields the following results:

Adjusted R Square	0.831
Independent Variables	Coefficients	Standard Error	t Stat	P-value
Intercept	1882	258	7.298	0.00076
P	-47.09	7.95	-5.923	0.00196
N	0.0014	0.0011	1.347	0.23573

Interpret what these coefficients mean.

c. Does price have a statistically significant effect on sales?

d. Does population have a statistically significant effect on sales?

e. What portion of the total variation in sales remains unexplained?

f. Barns Ennoble is considering selling toy barns in a new city, where the population is 142,000, and setting its barn price at $32. What level of annual sales would you expect in this new city (rounded to the nearest unit)?