Drill lifetime: A sample of 50 drills had a mean lifetime of

Last updated: 7/12/2022

Drill lifetime: A sample of 50 drills had a mean lifetime of 12.20 holes drilled when drilling a low-carbon steel. Assume the population standard deviation is 7.02. Part 1 of 3 (a) Construct a 95% confidence interval for the mean lifetime of this type of drill. Use tables or technology. Round your answers to at least two decimal places. The confidence interval is Part 2 of 3 (b) The manufacturer of the drills claims that the mean lifetime is greater than 13. Does this confidence interval contradict this claim? (Choose one), the confidence interval contains some/does not contain any values greater than 13, so the claim (Choose one) contradicted.