Sample Area Inspected m2 Imperfections 1 150 6 2 100 8 3 200 5 4 150 4 5 250 10 6 100 11 7 150 3 8 200 5 9 300 10 10 250 10 11 100 5 12 200 4 13 250 12 14 300 8 15 300 12 16 200 6 17 150 4 18 200 7 19 150 14 20 100 4 21 100 8 22 200 9 23 300 12 24 250 7 25 200 5 The number of imperfections in bond paper produced by a paper mill is observed over a period of several days. The table shows the the area inspected and the number of imperfections for 25 samples. Construct a control chart for the number of imperfections per square meter. Revise the limits if necessary, assuming special causes for the out of control points.