Help Solving A Single Population Mean Using The Normal Distribution

You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately σ=26.3. You would like to be 99% confident that your estimate is within 1 of the true population mean. How large of a sample size is required?

[Do not round mid-calculation. However, use a critical value rounded to three decimal places — this is important for the system to check answers correctly.]

n = ______

Solution

N = ((2.58*26.3)/1)^2= 4604.165316

approximately 4605 sample size will be needed