The mean amount xbar for all of the invoices for your company last month is not known. Based on your past experience, you are willing to assume that the standard deviation of invoice amounts is about $220. You take a random sample of 100 invoices.
Give your answer to the nearest integer.
Fill in the blank:
The 68-95-99.7 rule says that the probability is about 0.95 that xbar is within $ _______ of the population mean Mu?