7. Information supplied by a mail-order business for 12 cities is shown in Table P-7.

a. Determine the fitted regression line.

b. Calculate the standard error of the estimate.

c. Determine the ANOVA table.

d. What percentage of the variation in mail orders is explained by the number of

catalogs distributed?

e. Test to determine whether the regression slope coefficient is significantly differ

ent from zero. (Use the .01 significance level.)

f. Test for the significance of the regression using the

*F*

statistic from the ANOVA

table. (Use the .01 significance level.) Is the result consistent with the result in

part e? Should it be?

g. Forecast the number of mail orders received when 10,000 catalogs are distrib

uted with a 90% prediction interval.

## EXPERT ANSWER