A manufacturer of pharmaceutical products analyzes each batch of a product to verify the concentration of the active ingredient. The chemical analysis is not perfectly precise. In fact, repeated measurements follow a normal distribution with mean μ equal to the true concentration and standard deviation σ = 0.0072 grams per liter. Three analyses of one batch give concentrations of 0.8394 , 0.7375 , and 0.7506 grams per liter. To estimate the true concentration, give a 95 % confidence interval for μ . STATE: What is the concentration of the active ingredient in this batch? PLAN: We will estimate the true concentration by giving a 95 % confidence interval for the mean μ of the distribution. SOLVE: Find the mean of the measurements. (Enter your answer rounded to four decimal places.)