The mass of a checkweight, in milligrams, is measured 5417 times. Despite all the laboratory controls, the measurement came out a bit differently each time. Using the average of the 5417 measurements, the actual mass is estimated to be 1017.596 milligrams. The SD of the error distribution is estimated from the data to be 3.662 milligrams. What margin of error gives an interval of about 99% confidence? You may assume each measurement came out independently of the others, and that only chance measurement error occurred. 1017.596 ____ milligrams (Give the margin of error tto three decimal places, in milligrams.)