Sample No. of Incorrect Bills 1 6 2 5 3 11 4 4 5 0 6 5 7 3 8 4 9 7 10 2 a) Determine the value of p-bar, the mean factor defective. Then determine the control limits for the p-chart using a 99.73% confidence level (3 standard deviations). Is this process in control? If not, which sample(s) were out of control? b) How might you use the quality tools to determine the source of the billing defects and where you might start your improvement efforts to eliminate the causes.