Question

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

a) At the .01 level of significance, there is no evidence of a difference in the average price of business textbooks between the campus store and the Internet

b) H0: There is no singnificance difference in the average price of business textbooks between the campus store and the Internet (= 0)

H1: There is singnificance difference in the average price of business textbooks between the campus store and the Internet ( ≠ 0)

1. Test(s): two sample t test assuming equal variance
2. Decision rule: p-Value <= 0.01, we reject the null hypothesis

Book	Campus Store	Internet Price
1	55	50.95
2	47.5	45.75
3	50.5	50.95
4	38.95	38.5
5	58.7	56.25
6	49.9	45.95
7	39.95	40.25
8	41.5	39.95
9	42.25	43
10	44.95	42.25
11	45.95	44
12	56.95	55.6

3 Analysis:

Mean	47.68	46.12
Sd	6.66	6.02
Level of Significance	0.01
We will use two sample t test

t-Test: Two-Sample Assuming Equal Variances
	Campus Store	Internet Price
Mean	47.675	46.11666667
Variance	44.35977273	36.28242424
Observations	12	12
Pooled Variance	40.32109848
Hypothesized Mean Difference	0
df	22
t Stat	0.601131946
P(T<=t) one-tail	0.276948024
t Critical one-tail	2.508324553
P(T<=t) two-tail	0.553896047
t Critical two-tail	2.818756061

1. Conclusions:

Since p value is > level of significance we fail to reject the null hypothesis and conclude that there is no singnificance difference in the average price of business textbooks between the campus store and the Internet

a) What assumptions are necessary to perform this test?

We assume equal variance in the population of both the prices.

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%.

The answer for this is shown above in question no b).