Find the value of t n1, needed to construct an upper or lower confidence bound in each

Find the value of t_n−1,α needed to construct an upper or lower confidence bound in each of the situations in Exercise 1.

Data from exercise 1

Find the value of t_n−1,α/2 needed to construct a twosided confidence interval of the given level with the given sample size:

a. Level 90%, sample size 12.

b. Level 95%, sample size 7.

c. Level 99%, sample size 2.

d. Level 95%, sample size 29.