A supplier delivers several hundred batches of raw material to a company each year. The company is interested in a high yield from each batch of raw material (percent usable). Therefore, to investigate the consistency of this supplier, an experiment is done where five batches were selected at random and three yield determinations were made on each batch. We know that MSE = 1.80 1 2 3 4 5
74 68 75 72 79
76 71 77 74 81
75 72 77 73 79
Mean= 75 211/3 229/3 73 239/3

Required:
a. Give an appropriate model to analyze this data set, and state model assumptions.
b. Is there significant variability in the yield among batches (α = 0.05)? To get full credits, give null and alternative hypotheses, test statistic, p-value and conclusion.
c. Estimate all variance components.
d. What percentage of the overall variation in the yield is due to the batch differences?
e. Compute a 95% confidence interval for the average yield.