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?
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.