If, in a sample of n=16 selected from a normal population

Question 7: If, in a sample of n=16 selected from a normal population, Xbar = 56 and S = 12, what is the value of t stat if you are testing the null hypothesis Ho: mu = 50?
Question 8: In previous question, how many degrees of freedom does the t test have?
Question 9: For question #7 : If, in a sample of n=16 selected from a normal population, Xbar = 56 and S = 12, what is the value of t stat if you are testing the null hypothesis Ho: mu = 50?
Question 10: In questions #7 and #8 what are the critical values of t if the level of significance, alpha (fish) is 0.05 and the alternative hypothesis, H1, is mu not equal to 50?
Question 11: What is the critical value of alpha(fish) is .05 and an Ha:mu=60