LAB Chapter 8 Note: Remember the following for each lab, (1) Either print the lab and include your answers in the place provided or write your answers on regular paper, in either case students must manually answer each question in order, (2) Do not send a Word document with your answers, (3) If a question requires an explanation or an example you must provide one for full credit, (4) If a problem requires calculations then all mathematical steps need to be shown for credit. Students will use the standard Normal distribution 2 "' MO, 1) for large samples in this lab. 1. Construct a 94% confidence interval for the population mean, u. Assume the population has a normal distribution. A sample of 40 parttime workers had mean annual earnings of $3120 with a standard deviation of $677. Round to the nearest dollar. (Round to 2 decimals) 2. Construct a 93% confidence interval for the population mean, u. Assume the population has a normal distribution. A group of 36 randomly selected employees has a mean age of 25.4 years with a standard deviation of 3.8 years. Round to the nearest tenth. (Round to 3 decimals) 3. In order to set rates, an insurance company is trying to estimate the number of sick days that full time workers at a local bank take per year. Based on earlier studies it is known that the standard deviation is 13.2 days per year. (a) How large a sample must be selected if the company wants to be 95% confident that their estimate is within 2 days of the true mean? (Round the critical value to 2 decimals) (b) How large a sample must be selected if the company wants to be 97% confident that their estimate is within 24 hours of the true mean? (Round the critical value to 2 decimals) 4. Many people think that a national Iobby's successful fight against gun control legislation is reflecting the will of a minority of Americans. In a sample of 3,200 people, 2,250 were in favor of gun control legislation. Estimate the true mean of all Americans who are in favor of gun control legislation using a 94% confidence interval. Assume the population standard deviation is 490. (Round answer to 1 decimal)