A quality analyst wants to construct a control chart for controlling a packaging process. Each day last week, he randomly selected four packages and weighed each. The data from that activity appear below. Weight Day Package 1 Package 2 Package 3 Package 4 Monday 23 22 23 20 Tuesday 23 20 25 21 Wednesday 22 23 25 27 Thursday 18 15 20 19 Friday 19 20 22 22 a. What is the mean of all the sample means? [Select] b. Calculate upper and lower 3-sigma x-bar chart control limits that allow for natural variations. [Select] + c. Based on the x-bar chart, is this process in control? [Select] d. Calculate upper and lower limits for R-chart. [Select] e. Is the range chart in control? [Select] +