Question

4.38   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.

a) build a 90% two-sided confidence interval. What is the lower bound of the CI? (Round off your answer to three decimal places, i.e., X.XXX)

b) What is the upper bound of the CI? (Round off your answer to three decimal places, i.e., X.XXX)

c) Is it possible that the average failure rate is 10%? Yes/No. Explain.

d) Is it possible that the average failure rate is 11%? Yes/No. Explain.

e) The company made some changes resulting in 12 opened cans instead of 15. Determine a 95% two-sided confidence interval on the difference of proportions. What is the upper bound of the CI?

answer all parts please

Answer 1

a) The lower bound of the CI = 0.104

b) The upper bound of the CI = 0.196

c) Since 0.10 < lower bound of the confidence interval, so at 90% level of confidence or at 10% level of significance, we can conclude that he average failure rate is significantly less than 10%.

d) Since 0.11 is included in the confidence interval, so at 90% level of confidence or at 10% level of significance, we can conclude that he average failure rate is not significantly different from 11%.

e)

The upper bound of the CI = 0.109