probability and statistics

Five randomly selected boxes of 100 same-size screws have the following weights
(W) in kilograms: 0.2076, 0.2061, 0.2004, 0.1941, and 0.2047.

(a) Find the sample mean and standard deviation of these box weights
(b) Find a 95% confidence interval for the mean box weight, justifying any
assumptions that you make
(c) If fifty boxes are sampled at random and weighed, roughly how wide would your
95% confidence interval for the mean screw weight be?