For each medical procedure, Blue Shield pays a certain percentage of the average charge for that procedure. Each year Blue Shield needs to re-compute the amount paid to participating doctors. Since...

Extracted text: For each medical procedure, Blue Shield pays a certain percentage of the average charge for that procedure. Each year Blue Shield needs to re-compute the amount paid to participating doctors. Since surveying all of the doctors is not cost effective, Blue Shield takes a random sample and estimates the average charge. In order to set their payment schedule for tonsillectomy, Blue Shield wants to estimate the average charge with an error of estimation of no more than $50 and a 99% confidence level. A pilot sample of doctors was taken, and that sample's standard deviation was $175. How large of a sample of doctors should Blue Shield take in order to estimate the average charge for a tonsillectomy? 5.