following regression model: S = a + bP + cN. In your regressions, you usually look for a 5%- 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 0.617 Coefficient Standard Independent Variables S Error t Stat P-value Intercept 5048 2013 2.508 0.05397 P -66.37 18.72 -3.546 0.01647 N 0.0001 0.0056 0.026 0.97996 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. Harley Davidson is considering selling booster seats in a new city, where the population is 176,000, and setting its booster seat price at $65. What level of annual sales would you expect in this new city (rounded to the nearest unit)