A test is conducted on a new drug treatment to improve patient's memories. The scores of the 9 subjects before and after the new treatment are given on the table.

Before 55 57 57 64 64 67 70 71 71 After 57 63 67 67 70 72 73 80 81

What is the 95% confidence interval for the improvement of test scores after the new treatment is given to the patients?

A test is conducted on a new drug treatment to improve patient's memories. The scores of the 9 subjects before and after the new treatment are given on the table.

Before 55 57 57 64 64 67 70 71 71 After 57 63 67 67 70 72 73 80 81

What is the 95% confidence interval for the improvement of test scores after the new treatment is given to the patients?

D. [3.17 , 8.83]

A. [3.63 , 8.37]

C. [3.35 , 8.65]

B. [3.69 , 8.31]