The mean amount μ for all 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 $343. You take a random sample of 148 invoices. Apply the Central Limit Theorem and the 68-95-99.7 Rule to complete the following sentence: "The probability is about 0.95 that the sample mean is within _________ of the population mean μ ."