A tele-marketing company wants to know if sales go up as theycall more people per day but spend less time per call. Thefollowing is the data from nine randomly selected days. Theinformation is the number of calls the salesperson makes in a dayand the total amount of sales (in thousands of dollars).

Calls            25      29     33      37     43      48     52      55     67

Sales           3.7     4.2    4.2     5.0    4.7     5.3    4.9     5.6     5.9

a. Calculate ∑X, ∑X², ∑Y, ∑Y², ∑XY

b. Calculate SS_XX, SS_YY, andSS_XY.

c. Use the information from parts (a) and (b) to generate theestimated OLS line.

d. Interpret the estimated slope coefficient from your line inpart c.

e. Predict the amount of sales for the fourth observation in thedata set.

f. Calculate the residual for that observation.

g. Construct the ANOVA table for this situation.

h. Calculate the coefficient of determination.

i. Interpret the coefficient of determination.

j. Using alpha = 0.05, use a model test to see if a linearrelationship exists between the number of calls and sales.

k. A positive relationship is anticipated between these twovariables. At alpha = 0.05, test to see if the evidence supportsthat anticipated sign.

l. Construct a 98% confidence interval for the population slopecoefficient.