One step in the manufacture of a certain metal clamp involves the drilling of four holes. In a sample of 150 clamps, the average time needed to complete this step was 71 seconds and the standard deviation was 11 seconds. Find a 90% confidence interval for the mean time needed to complete this step. (Round the final answers to three decimal places.) The 90% confidence interval is
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Adi S.
One of the steps used to manufacture a metal clamp involves the drilling of three holes. We want to estimate the mean time it takes to drill the holes for each clamp. If we assume that the population standard deviation is 10 seconds, how large of a sample will we need in order to measure drilling time with a margin of error of 1.2 at a 99% confidence level? 18 clamps 461 clamps 295 clamps 22 clamps
Anna D.
1. Efficient manufacturing: Efficiency experts study the processes used to manufacture items in order to make them as efficient as possible. One of the steps used to manufacture a metal clamp involves the drilling of three holes. In a sample of 50 clamps, the mean time to complete this step was 46.5 seconds. Assume that the population standard deviation is =σ 11 seconds. Round the critical value to no less than three decimal places. Construct a 99.9% confidence interval for the mean time needed to complete this step. Round the answer to at least one decimal place.
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