Test the given claim using the x = 0.05 significance level and assuming that the populations are normally distributed.

Claim: The treatment population and the placebo population have the same mean.
Treatment group: n = 5, x = 71, s = s = 5.4.
Placebo group: n= 6, 81, 8 = 5.1.

a. The test statistic is:___________
b. The positive critical value is:_________
c. The negative critical value is:_____________