3.(5 points) A crossover study was conducted to investigate whether oat bran cereal helps to lower serum cholesterol in hypercholesterolemic males. Fourteen such individuals were randomly placed on a diet that included either oat bran or corn flakes; after two weeks, their low-density lipoprotein (LDL) cholesterol levels were recorded. Each man was then switched to the alternative diet. After a second two-week period, the LDL cholesterol level of each individual was again recorded. The data from this study are shown below:

Subject

Corn flakes

Oat bran

1

4.61

3.84

2

6.42

5.57

3

5.4

5.85

4

4.54

4.8

5

3.98

3.68

6

3.82

2.96

7

5.01

4.41

8

4.34

3.72

9

3.8

3.49

10

4.56

3.84

11

5.35

5.26

12

3.89

3.73

13

2.25

1.84

14

4.24

4.14

(1)Are the two samples of data paired or independent?

(2)What are the appropriate null and alternative hypotheses?