Consider the population of 140 observations that are presented in Table P-12. The Marshall Printing.

Consider the population of 140 observations that are
presented in Table P-12. The Marshall Printing Company wishes to estimate the
relationship between the number of copies produced by an offset printing
technique (X) and the associated direct labor cost (Y). Select a random sample
of 20 observations.

a. Construct a scatter diagram.

b. Compute the sample correlation coefficient.

c. Determine the fitted regression line.

d. Plot the fitted line on the scatter diagram.

e. Compute the standard error of estimate.

f. Compute the coefficient of determination and interpret
its value.

Consider the population of 140 observations that are
presented in Table P-12. The Marshall Printing Company wishes to estimate the
relationship between the number of copies produced by an offset printing
technique (X) and the associated direct labor cost (Y). Select a random sample
of 20 observations.

a. Construct a scatter diagram.

b. Compute the sample correlation coefficient.

c. Determine the fitted regression line.

d. Plot the fitted line on the scatter diagram.

e. Compute the standard error of estimate.

f. Compute the coefficient of determination and interpret
its value.

g. Test the hypothesis that the slope, , of the population
regression line is zero.

h. Calculate a point forecast and a 90% prediction interval
for the direct labor cost if the project involves 250 copies.

i. Examine the residuals. Does it appear as if a simple
linear regression model is appropriate for these data? Explain.

Table p-12