Drill lifetime: A sample of 50 drills had a mean lifetime of 12.54 holes drilled when drilling a low-carbon steel. Assume the population standard deviation is 7.11. Part: 0 / 3 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: 1 / 3 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 (Choose one) v values greater than 13, so the claim (Choose one) v contradicted. is is not

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