Refer to given problem. Give a 95% confidence interval for the difference in the proportions of defective items made by suppliers A and B.
Problem
A company that makes electronic devices for use in hospitals needs to decide on one of two possible suppliers for a certain component to be used in the devices. The company gathers a random sample of 200 items made by supplier A and finds that 12 items are defective. An independent random sample of 250 items made by supplier B reveals that 38 are defective. Is one supplier more reliable than the other? Explain.