Question 1062014
the decision rule will be a t (df=9, 0.95)>1.833.  If t is greater than that number reject; if less than or equal to than fail to reject.
t=(12-10)/3/sqrt(10)=2*sqrt(10)/3=2.108
Reject Ho and conclude that the population mean is greater than 10. It is interesting that a two-tailed test would not be significant in this instance.