Question

A marketing consultant was hired to visit a random sample of five sporting goods stores across the state of California. Each store was part of a large franchise of sporting goods stores. The consultant taught the managers of each store better ways to advertise and display their goods. The net sales for 1 month before and 1 month after the consultant's visit were recorded as follows for each store (in thousands of dollars):

Store	1	2	3	4	5
Before visit	51.8	99.4	49.2	77.4	43.2
After visit	67.6	107.2	57.8	81.2	41.9

Do the data indicate that the average net sales improved? Use α = 0.10. (Let d = before − after.)

What are we testing in this problem?

a.paired difference

b.difference of means  

c.single proportion

d.difference of proportions

e.single mean

(a) What is the level of significance?

___________
State the null and alternate hypotheses.

aH₀: μ_d = 0; H₁: μ_d ≠ 0

bH₀: μ_d = 0; H₁: μ_d < 0   

cH₀: μ_d > 0; H₁: μ_d = 0

dH₀: μ_d = 0; H₁: μ_d > 0

(b) What sampling distribution will you use? What assumptions are you making?

aThe standard normal. We assume that d has an approximately uniform distribution.

bThe Student's t. We assume that d has an approximately normal distribution.   

cThe Student's t. We assume that d has an approximately uniform distribution.

dThe standard normal. We assume that d has an approximately normal distribution.

What is the value of the sample test statistic? (Round your answer to three decimal places.)

__________
(c) Find (or estimate) the P-value. (Round your answer to four decimal places.)

____________

Answer 1