Small boxes of NutraFlakes cereal arelabeled "net weight 10 ounces." Each hour ,random samples of size n=4 boxes are weighed to check process control. five hours of observations yielded the following:
WEIGHT
TIME BOX 1 BOX 2 BOX 3 BOX 4
9 A.M 9.8 10.4 9.9 10.3
10 A.M 10.1 10.2 9.9 9.8
11 A.M 9.9 10.5 10.3 10.1
NOON 9.7 9.8 10.3 10.2
1 P.M 9.7 10.1 9.9 9.9
Using these data, construct for x- and R-charts. Is the process in control? What other steps should the QC department follow at this point?