Finding Confidence Intervals
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Minting Quarters Quarters are currently minted with weights having a mean of 5.760 g and a standard deviation of 0.062 g. New equipment is being tested in an attempt to improve quality by reducing variation. A simple random sample of 24 quarters is obtained from those manufactured with the new equipment, and this sample has a standard deviation of 0.049 g. Use the sample results to construct a 95% confidence interval estimate of σ, the standard deviation of the weights of quarters made with the new equipment. Based on the confidence interval, does the new equipment appear to produce a standard deviation that is clearly lower than the standard deviation of 0.062 g from the old equipment? Based on the results, does the new equipment appear to be effective in reducing the variation of the weights?
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Solution Summary
The solution finds the confidence intervals for minting quarters equipment. How the new equipment appears to be effective in reducing the variation of the weight is determined.
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