A quality analyst wants to construct a sample mean chart for controlling a packaging process. Each day last week, he randomly selected four packages and weighed each. The data from that activity appears below. The population standard deviation, o, is not known. Weight Package 3 Package 1 Package 2 Package 4 21 Day Monday Tuesday Wednesday Thursday Friday 19 21 19 20 20 (a) Calculate all sample means for each day and the mean of all sample means (b) Calculate upper and lower control limits which covers 95% of all samples for Xbar chart and R-chart (when n=4, A2-0.729, D-2.282, D, 0; when n 5, A2 0.577, D, -2.115, D, 0;). (Hint: you only need the right number(s) for this problem instead of all of them) (c) Please HAND draw the SPC charts (Xbar and R charts) and give the conclusion. And is this process in control? (Please use the back if you need more space for this