A manufacturer claims that a new engineering design yields an average lifetime of 15 months for a certain part. An independent researcher conducts a study on a sample of 70 such parts with the new design and records an average lifetime of 14.6 months. Does the study disprove the manufacturer's claim? Find the p-value for the test. Assume a population standard deviation of 1.8 months. A) 0.1256 B) 0.0785 C) 0.0314 D) 0.0628 E) 0.0157
