A random sample of 900 refrigerators contains 79 defective units. Estimate the process fraction nonconforming.
a. What is the distribution of nonconforming units? Can this be approximated? With what?
b. Test the hypothesis that the true fraction nonconforming in the refrigerator manufacturing process is 0.10 using a = 0.05.
c. Construct a 90% two-sided confidence interval on the true fraction nonconforming in the refrigerator manufacturing process.