Astudy was conducted to determine if a certain treatment has any effect on the amount of metal removed in a pickling operation. a random sample of 100 pieces was immersed in a bath for 24 hours without the treatment, yielding an average of 12.2 millimeters of metal removed and a sample standard deviation of 1.1 millimeters. a second sample of 200 pieces was exposed to the treatment, followed by the 24-hour immersion in the bath, resulting in an average removal of 9.1 millimeters of metal with a sample standard deviation of 0.9 millimeter. compute a 98% confidence interval estimate for the difference between the population means. does the treatment appear to reduce the mean amount of metal removed?