Please use the accompanying Excel data set or accompanying Text file data set when completing the following exercise. The yield of a chemical process is being studied. From previous experience, yield is known to be normally distributed and = 3. The past five days of plant operation have resulted in the following yields 91.6, 88.75, 90.8, 89.50, and 91.2. Find a 95% two-sided confidence interval on the true mean yield. (a) Calculate the sample mean. Round your answer to 2 decimal places. x = 90.37 (b) Calculate the 95% two-sided confidence interval on the true mean yield. Round your answers to 1 decimal place. 89.1 SHS 914 Statistical Tables and Charts