Sales data were collected from a small bookstore. The following is an equation for the regression line of the data.

Sales=7.97+0.923NumberofSalespeopleWorking

The assumptions and conditions for regression aremet, and fromtechnology, it is known that SEb1=0.1030 and se=1.661. Use the data to answer parts a through c.

Number_of_Salespeople_Working, "Sales_(in_$1,000s)"

2, 8

4, 10

6, 14

8, 17

9, 18

10, 18

11, 20

17, 24

15, 20

18, 23

x = 10.0, y = 17.2

SD(x) = 5.37, SD(y) = 5.20

a) Find the predicted sales on a day with 500 employees working.

The predicted sales on a day with 500 employees working is_________ thousand dollars.

(Round to two decimal places asneeded.)

b) Find the95% prediction interval for Sales on a day with 500 employees working.

The interval in thousands is

( , )

(Round to two decimal places asneeded.)

c) Is this last interval likely to beuseful? Choose the correct answer below.

A.

No. There are too many outliers for the regression model to be accurate enough to draw any meaningful conclusions.

B.

Yes. All of the necessary assumptions and conditions for regression aremet, so any prediction intervals derived from the model will provide meaningful information about the data.

C.

No. There are too few data points to draw any conclusions from the prediction intervals.

D.

No. Not only is the interval too wide to draw any meaningfulconclusions, but extrapolating what sales will be with 500 employees based on data with up to 17 employees is not likely to be accurate at all.

Answer rating: 100% (QA)

The Answer is in the image, click to view ... View the full answer