Question

In: Statistics and Probability

The manager of a cosmetics section of a large department store wants to determine whether newspaper...

The manager of a cosmetics section of a large department store wants to determine whether newspaper advertising affects sales.  She randomly selects 10 items currently in stock that are priced at their usual competitive value, and she records the quantity of each item sold for a one-week period.  Then, without changing their price, she places a large ad in the newspaper, advertising the 10 items.  Again, she records the quantity sold for a one-week period.  Her data are listed below:                                

Item

# Sold Before Ad

# Sold After Ad

1

18

24

2

3

7

3

16

19

4

23

23

5

15

5

6

7

11

7

13

12

8

16

12

9

20

25

10

14

20

Test whether placement of the ad resulted in a significant increase in sales, with an alpha of .05.

a. State the H0 and H1 hypotheses, in statistical notation, and identify the critical t value(s).

b. Calculate standard error and the observed t-statistic.  What is your decision regarding the null hypothesis?  Why?

c. State your results in nonstatistical terms.

d. State the type of t-test you used for problems A, B, and C, above, and explain why each test was the appropriate one to choose.

Solutions

Expert Solution

orchestra answered 1 year ago
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