### Solution Found!

# 9-21. Reconsider the chemical process yield data from Exercise 8-9. Recall that 3, yield

**Chapter 9, Problem 9-21**

(choose chapter or problem)

**QUESTION:**

9-21. Reconsider the chemical process yield data from Exercise 8-9. Recall that 3, yield is normally distributed and that n 5 observations on yield are 91.6%, 88.75%, 90.8%, 89.95%, and 91.3%. Use 0.05. (a) Is there evidence that the mean yield is not 90%? (b) What is the P-value for this test? (c) What sample size would be required to detect a true mean yield of 85% with probability 0.95?

### Questions & Answers

**QUESTION:**

9-21. Reconsider the chemical process yield data from Exercise 8-9. Recall that 3, yield is normally distributed and that n 5 observations on yield are 91.6%, 88.75%, 90.8%, 89.95%, and 91.3%. Use 0.05. (a) Is there evidence that the mean yield is not 90%? (b) What is the P-value for this test? (c) What sample size would be required to detect a true mean yield of 85% with probability 0.95?

**ANSWER:**

(a) Yes, there is evidence that the mean yield is not 90%.