stats
posted by chris .
The president of a large university wishes to estimate the average age of the students presently enrolled. From past studies, the standard deviation รณ is known to be 2 years. A sample of 50 students is selected and the mean is found to be 23.3 years.
a. Find the 99% confidence interval of the population.
b. Find the 99% confidence interval for the population standard deviation.

a. Use the equations from the previous post.
b. Sorry, I don't know how to do this.