Tai Chi is often recommended as a way in improve balance and flexibility in the elderly.Below are before-and-after flexibility ratings (on a 1 to 10 scale, 10 being most flexible) for 8 men in their 80's who took Tai Chi lessons for six months.

Subject

A

B

C

D

E

F

G

H

Flexibility rating after Tai Chi

2

4

3

3

3

4

5

10

Flexibility rating before Tai Chi

1

2

1

2

1

4

2

6

Does the data provide convincing evidence that men in their 80's who take tai chi lessons for six months gain in flexibility ratings? carry out a paired t test.