1) You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately ?=62.3?=62.3. You would like to be 95% confident that your estimate is within 2 of the true population mean. How large of a sample size is required?
Use a z* value accurate to TWO places for this problem. (Not z = 2)
n =
2)You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately ?=40.8?=40.8. 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?
As in the reading, in your calculations:
--Use z = 1.645 for a 90% confidence interval
--Use z = 2 for a 95% confidence interval
--Use z = 2.576 for a 99% confidence interval.