The Variance in drug weights is critical in the pharmaceutical industry. For a specific drug, with weights measured in grams, a sample of 18 units provided a sample variance of s^2=.36.
a. Construct a 90% confidence interval estimate of the populatiion variance for the weight of this drug.
b. Construct a 90% confidence interval estimate of the population standard deviation.
Please explain how to do these, I've searched throuh my book with no luck.