The US Bureau of Labor Statistics collects information on the ages of people in labor force. A random sample of 50 people from the population is selected, with sample mean ī = 36.4 years. Assuming the...

Extracted text: The US Bureau of Labor Statistics collects information on the ages of people in labor force. A random sample of 50 people from the population is selected, with sample mean ī = 36.4 years. Assuming the population standard deviation (of the ages) is 12.1 years. a) Find a 95% confidence interval for the population mean age u. b) Determine the sample size needed in order to be 95% confident that the population mean u is within 0.5 year of the sample mean ?