2. A simple random sample of 50 items from a population with o = 6 resulted in a sample mean of 32. a. Provide a 90% condence interval for the population mean. b. Provide a 95% condence interval for the population mean. e. PTovide a 99% condence interval for the population mean. 3. A simple random sample of 60 items resulted in a sample mean of 80. The population standard deviation is (I = 15. a. Compute the 95% condence interval for the population mean. b. Assume that the same sample mean was obtained from a sample of 120 items. Provide a 95% condence interval for the population mean. c. What is the effect of a larger sample size on the interval estimate? 4. A 95% condence interval for a population mean was reported to be 152 to 160. If U = 15, what sample size was used in this study