Amanufacturer 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 equal to the true concentration and standard deviation grams per liter. three analyses of one batch give concentrations of , , and grams per liter. to estimate the true concentration, give a confidence interval for . 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 = 0.0067 grams per liter. three analyses of one batch give concentrations 0.8225, 0.8737, and 0.91 grams per liter.

the mean (±0.0001) of the measurements is .

the 95% confidence interval for μ (±0.0001) is .