Originally Posted by

**neilbuster** Hi,

I could not find the answer of these two questions, can anyone help me ?

thanks in advance.

1- A tool manufacturer’s choose randomly 10 pieces from a batch. The measured weights are listed below. Supposing the distribution as normal, please calculate 99% CI of the population variance.

(51, 50, 60, 53, 59, 54, 56, 51, 59, 58)

2- 450 pieces of a machine tool have been produced with a variance of 300 grams2 . Please find for variance the CI of 95%. (solve the problem as a large sample)