Question

2008	2007
Sample Size	36	36
Sample Mean	75.1944	69.4167
Sample Standard Deviation	15.0177	7.3149
df	50
Confidence Interval (in terms of 2008 - 2007)
Confidence Coefficient	0.80
Lower Limit	2.1621
Upper Limit	9.3935
Hypothesis Test (in terms of 2008 - 2007)
Hypothesized Value	0
Test Statistic
p-value (Lower Tail)
p-value (Upper Tail)
p-value (Two Tail)

	2008-2007
Sample Size	36
Sample Mean	5.7778
Sample Standard Deviation	18.2790
Confidence Interval (in terms of 2008 - 2007)
Confidence Coefficient	0.80
Lower Limit	1.7984
Upper Limit	9.7571
Hypothesis Test (in terms of 2008 - 2007)
Hypothesized Value	0
Test Statistic
p-value (Lower Tail)
p-value (Upper Tail)
p-value (Two Tail)

During 2008, JCPenney took steps to improve customer service in order to increase their customer satisfaction score. A random sample of 36 JCPenney customers in the 4th quarter of 2007 and a random sample of 36 JCPenney customers in the 4th quarter of 2008 were surveyed and their customer satisfaction score entered into Excel. Can JCPenney conclude the average 2008 customer satisfaction score is greater than the average 2007 customer satisfaction score at α=.005? Based on this paragraph of text, use the correct excel output above to answer the following question.

What would the P-value be for H_a: μ₂₀₀₇ - μ₂₀₀₈ < 0?

	a.	.025 < P-value < .05
	b.	.95 < P-value < .975
	c.	.975 < P-value < .99
	d.	.01< P-value < .025
	e.	None of the answers is correct

Answer 1

The test statistic under the null hypothesis is:

Using the values in the table we get:

t = 11.379

The corresponding p-value is 8.72*10^(-16)

Since, the p-value is less than 0.005 we rejcet the null hypothesis at 0.5% level of significance and conclude that the average 2008 customer satisfaction score is greater than the average 2007 customer satisfaction score at α=.005.

What would the P-value be for Ha: μ2007 - μ2008 < 0?

option e none of the answers are correct.