A bank officer wishes to study how many credit cardholders attempt to exceed their established credit limits. To accomplish this, the officer randomly selects a weekly sample of 100 of the cardholders who have been issued credit cards by the bank, and the number of cardholders who have attempted to exceed their credit limit during the week is recorded. The numbers of cardholders who exceeded their credit limit in 20 consecutive weekly samples of 100 cardholders are. respectively, 1,4, 9, 0,4, 6, 0, 3, 8, 5, 3, 5, 2, 9, 4,4, 3, 6, 4, and 0. Construct a control chart for the data and determine if the data are in statistical control. If 12 cardholders in next week's sample of 100 cardholders attempt to exceed their credit limit, should the bank regard this as unusual variation in the process?