You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately=56.1

You would like to be 99% confident that your estimate is within 2.5 of the true population mean. How large of a sample size is required?

n=

Do not round mid-calculation. However, you are encouraged to use a critical value accurate to three decimal places this is important for the system to be able to give hints for incorrect answers.