Question

I think this question should use t-Test: paired two sample for means, but my friend think it should use t-test: t-test: Two-sample assuming equal variances. So, I need someone to help me explain which method is correct and answer the following question. Thanks!!

A professor in the School of Business wants to investigate the prices of new textbooks in the campus bookstore and the Internet. The professor randomly chooses the required texts for 12 business school courses and compares the prices in the two stores. The results are as follows:

Book	Campus Store	Internet Price
1	$55.00	$50.95
2	47.50	45.75
3	50.50	50.95
4	38.95	38.50
5	58.70	56.25
6	49.90	45.95
7	39.95	40.25
8	41.50	39.95
9	42.25	43.00
10	44.95	42.25
11	45.95	44.00
12	56.95	55.60

1. At the .01 level of significance, is there any evidence of a difference in the average price of business textbooks between the campus store and the Internet? Use Excel and the classical method.
2. Hyps: H₀:

H₁:

2. Test(s):

3. Decision rule:

4. Analysis:

5. Conclusions: (1)

(2)

(3)

(4)

2. What assumptions are necessary to perform this test?   

3. Find the p-value in (a)? Using the p-value, Is there any evidence of a difference in the average price of business textbooks between the campus store and the Internet? Use Excel and the p-value method and alpha = 1%.

1. Hyps: H₀:

H₁:

2. Test(s):

3. Analysis:

p-value:

4. Conclusions: (1)

(2)

(3)

(4)

Answer 1

This is a t-Test: paired two sample for means.

The hypothesis being tested is:

H₀: µ₁ = µ₂

H₁: µ₁ ≠ µ₂

47.67500	mean Campus Store
46.11667	mean Internet Price
1.55833	mean difference (Campus Store - Internet Price)
1.60409	std. dev.
0.46306	std. error
12	n
11	df
3.365	t
.0063	p-value (two-tailed)

The p-value is 0.0063.

Since the p-value (0.0063) is less than the significance level (0.01), we can reject the null hypothesis.

Therefore, we can conclude that there is a difference in the average price of business textbooks between the campus store and the Internet.