Continuation of Exercise 4.38. The company has made improvements and has repeated the experiment. In this iteration, 12 opened. Using a 95% two-sided confidence interval on the difference in proportions, is it possible to cite improvement?
In exercise During shipment testing, product was flown from Indianapolis to Seattle and back again to simulate 4 takeoffs and landings which can cause cans to open due to pressure changes. Prototype units of the 100 were shipped and 15 opened. Using a 90% two-sided confidence interval, determine if it is possible that the average failure rate is 11%.