Can you help me solve this ?

Name: (26 answers, 4 pis ea) 1. Forbes gave the following data about percent return on capital for some stocks: 1.7, 2.3, 0.8, 1.6, 1.7, 2.1, 2, 1.4, 2.5, 2.3, 1.7, 1, 0.7, 1.1, 4.3, 1.6, 1.5, 2.3 (percentage return on capital is normally distributed and s = 0.816%) Find (round to nearest hundredths): a. The 85% confidence intervals for the population mean b. The 98% confidence intervals for the population mean c. How many more (than the original 18) would they need to sample to be 95% confident to be within 0.1 percent of the population mean