Question

3. We are interested in estimating the mean annual income of adults in Sweetwater County. To accomplish this, we select a random sample of 65 adults residing in the county. We find that the sample mean is $47,250, and we know from the previous studies that the population standard deviation is $3,555. a) Calculate a 95% confidence interval for the population mean, and interpret the result. B) Calculate a 99% confidence interval for the population mean, and interpret the result. c) If the margin of error (maximum error of estimate) is reduced to $650, what should be the required sample size? Assume the confidence level is 95%.

Answer 1