I'm having trouble trying to solve #2. What are the answers to (b.) and (c.) ? Please show work.

2. Rene, Raul and Will, of Hu's P-Hat Now! a statistics rap crew saw their musical career fail when their debut single, "Red Vines!" was re-recorded as "Blurred Lines!" and it topped the charts! They consoled themselves by finding the critical values (z, t or x2) for the following. (2pts. each.) a. Alpha in the left tail is 2.5%, sample size is 50 and sigma is known. b. alpha is 1%, sample variance is 2.8 and the sample size is 24. c. C.L. = 95%, sample size is 30; find (X2R &xx2,, 2-tails)