1. Professor Andy Neill measured the time (in seconds) required to catch a falling meter stick for 12 randomly selected students' dominant hand and non-dominant hand. Professor Neill wants to know if the reaction time in an individual's dominant hand is less than the reaction time in his or her non-dominant hand. A coin flip is used to determine whether reaction time is measured using the dominant or non-dominant hand first. Conduct the test at the =0.05 level of significance. The data obtained are presented in the following table:

Student	Dominant hand, Xi	Non-dominant hand, Yi
1	0.177	0.179
2	0210	0.202
3	0.186	0.208
4	0.189	0.184
5	0.198	0.215
6	0.194	0.193
7	0.160	0.194
8	0.163	0.160
9	0.166	0.209
10	0.152	0.164
11	0.190	0.210
12	0.172	0.197

2. In the Spacelab Life Sciences 2 payload, 14 male rats were sent to space. Upon their return, the red blood cell mass (in milliliters) of the rats was determined. A control group of 14 male rats was held under the same conditions (except for space flight) as the space rats, and their red blood cell mass was also determined when the space rats returned. The project, led by Dr. Paul X. Callahan, resulted in the data listed in the table below. Does the evidence suggest that the flight animals have a different red blood cell mass from the other group of animals (control) at the =0.05 level of significance?

Flight	Control
8.59	8.65
8.64	6.99
7.43	8.40
7.21	9.66
6.87	7.62
7.89	7.44
9.79	8.55
6.85	8.70
7.00	7.33
8.80	8.58
9.30	9.88
8.03	9.94
6.39	7.14
7.54	9.14

3. Low-birth-weight babies are at increased risk of respiratory infections in the first few months of life and have low liver stores of vitamin A. In a randomized, double-blind experiment, 130 low-birth-weight babies were randomly divided into two groups. Subjects in group 1(the treatment group, n=65) were given 25,000 IU of vitamin A on study days 1, 4, and 8 where study day 1 was between 36 and 60 hours after delivery. Subjects in group 2 (the control group, n=65) were given a placebo. The treatment group had a mean serum retinol concentration of 45.77 micrograms per deciliter (mg/dL), with a standard deviation of 17.07 mg/dL. The control group had a mean serum retinol concentration of 12.88 mg/dL, with a standard deviation of 6.48 mg/dL. Does the treatment group have a higher standard deviation for serum retinol concentration than the control group at the =0.01 level of significance? It is known that serum retinol concentration is normally distributed.