Choose the letter of the correct answer.1.The yield of a chemical process is being studied. From previous experience yield is known to be normally distributed and σ = 3. The past 6 days of plant...

Choose the letter of the correct answer. 1.The yield of a chemical process is being studied. From previous experience yield is known to be normally distributed and σ = 3. The past 6 days of plant operation have resulted in the following percent yields: 91.6, 88.75, 90.8, 89.95, and 91.3. You are asked to find a 90% two-sided confidence interval on the true mean yield. What is the sample mean? A. 90 B. 90.48 C. 3 D. 0.90 2.In Problem 11, what is the sample size? A. 5 B. 6 D. 3 D. 0.90 3.In problem 11, where do you look for the critical z limits? A. Cumulative normal distribution table C. Chi-squared distribution table B. T-distribution table D. F- distribution table