Problem 2E

The specification for the pull strength of a wire that connects an integrated circuit to its frame is 10 g or more. In a sample of 85 units made with gold wire, 68 met the specification, and in a sample of 120 units made with aluminum wire, 105 met the specification. Find a 95% confidence interval for the difference in the proportions of units that meet the specification between units with gold wire and those with aluminum wire.