The yield of a chemical process is being studied. From previous experience with this process the standard deviation of yield is known to be 2.9. The past 5 days of plant operation have resulted in the following yields (given in percentages): 91.6, 88.75, 90.8, 89.95 and 91.3%.

A)What is the numerical value of the sample mean yield? Answer to two decimal places.

B)Test the hypothesis that the mean yield is not equal to 90%. Use alpha = .01. What is the numerical value of the test statistic? Answer to two decimal places.

C)If the true population mean yield is 92%, what is beta, the probability of Type II error? Answer to three decimal places. (Remember that this is a 2-sided test and that alpha is .01.)