We are evaluating the sheet metal scrap rate in a contractor proposal. Based on a sample of 24 parts you calculate a mean rate of 6.50% (treat as 6.50) and a standard deviation of 1.20. Calculate a 80% confidence interval to be used to support negotiations. (Carry intermediate calculations to three decimal places.) 6.18 ≤ μ ≤ 6.82 6.41 ≤ μ ≤ 6.59 6.08 ≤ μ ≤ 6.92 6.43 ≤ μ ≤ 6.57