4.- At the Los Angeles Hospital, certain doctors carried out an experiment in which the arteries of 105 sedentary people were photographed and given the photograph to take with them. The same medical procedure was applied to 105 other people, but the photograph was not given to them. After 6 months, the group with a photograph had lost an average of 17.6 pounds, while the group without a photograph had lost an average of 11.0 pounds. Suppose that the data in the photo file contains the weights that the members of each group lowered. In a proper one-tailed test with a level of 0.05, was the mean weight lost by the group with a photo significantly greater than that of the group without a photo? Identify and interpret the p-value for the test.

photo file information:

Photography	No Photography
19.8	3.8
16.8	6.3
22.0	14.3
15.0	9.9
9.3	5.0
13.2	11.8
20.2	4.3
21.9	8.2
23.9	20.5
23.2	6.2
9.7	6.2
14.3	10.4
21.9	7.0
19.9	16.4
13.3	5.1
14.0	20.3
21.7	3.9
21.4	9.4
18.7	1.7
13.1	10.2
25.8	17.3
23.1	16.1
20.1	12.7
12.0	6.9
23.5	21.4
23.8	12.9
16.1	13.4
14.1	2.4
27.0	6.6
15.7	4.4
6.0	16.3
13.5	7.1
20.2	26.3
22.6	12.9
9.0	7.5
24.9	2.4
11.6	22.2
21.9	8.4
22.6	15.9
25.7	6.1
6.4	15.2
17.2	13.3
16.6	14.8
30.3	8.6
12.9	5.6
8.9	7.3
7.2	3.3
8.1	1.5
16.4	15.8
13.9	11.8
14.5	3.2
21.7	16.8
18.2	16.4
14.4	14.8
21.4	7.8
17.9	3.7
14.9	8.0
20.2	6.7
9.9	13.6
27.4	7.3
17.1	14.7
9.2	15.1
27.1	8.9
16.0	15.4
6.1	13.9
10.4	6.1
10.9	6.2
17.8	8.9
14.6	6.3
14.3	12.0
25.0	6.3
23.7	7.4
20.2	13.3
17.8	14.7
30.9	8.8
17.0	13.0
22.5	1.6
16.6	5.0
13.2	3.7
8.7	9.6
31.6	10.5
14.1	10.4
24.4	13.9
17.4	14.0
20.8	16.9
19.0	12.4
15.5	1.4
16.7	9.3
20.2	14.4
24.9	7.8
9.6	14.2
22.4	28.3
13.2	22.8
19.5	12.6
15.2	25.2
19.2	1.8
24.1	13.5
13.5	11.5
12.8	12.4
13.5	19.6
17.5	9.8
13.6	14.6
21.3	18.4
20.8	15.5
17.2	17.3

5.- The New York Stock Exchange reported that the average number of shares in direct possession of senior citizens is 4.3, compared to 2.0 shares for "young millionaires." Suppose that the data in the shares file contains the number of shares owned by the people in a sample of each age group. Based on the results of a two-tailed test with a level of 0.10, comment on whether the difference between the sample means could have occurred by chance. Identify and interpret the p-value for the test.

shares file information:

Seniors	Boomers
4	5
3	1
4	0
2	2
3	2
5
6
3
7
6

6.- With the results of the sample from exercise 5, develop and interpret the 90% confidence interval for the difference between the population means. Is the hypothetical difference (0.00) within the range? Given the presence or absence of the value 0.00 within the interval, does this coincide with the results of the hypothesis test carried out in the previous exercise?

7. An engineer measured the hardness ratings of a sample of hardened conveyor belt bearings using two different methods. Her company uses the first method, and she knows the second is used by various companies in the industry. Using the data from the hardness file, she uses the 0.05 significance level to compare the mean of the hardness ratings of the two samples, commenting on the possibility that the difference between the means may have occurred by chance. Identify and interpret the p-value for the test.

hardness file information:

Sample 1	Sample 2
146.8	117.5
162.2	136.4
145.0	148.6
141.9	149.3
139.4	163.0
191.5	110.2
167.7	157.6
140.3	134.9
132.5	124.8
	137.6