Scientists have found a new drug for patients with anemia problems.
However, they need to test the drug they have found before placing it on the market.
The team who found the drug performed blood tests before and after drug use by a group of 20 people and recorded the hemoglobin values they found in the table.
Hb value in blood results was examined and given on the basis of subject in the table below.

a) Test whether there is a difference in Hb value before and after the drug at 5% significance level.

b) Hb Value should be 15.5 on average. When considering the drug before and after the drug, test whether the Hb value of the subjects is less than the average Hb value.

Test subject 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Before medication 9,9 10,2 8,7 9,2 8,6 10,2 9,9 10,2 11,5 10,9 7,2 9,9 9,3 9,7 10,1 12,3 11,0 9,8 10,5 7,8

Post medication 10,1 12,6 7,5 9,3 8,7 17,7 15,3 18,9 11,6 18,1 8,9 18,9 8,6 12,9 10,2 15,5 13,2 9,9 10,6 8,1