Bob, the CEO of a large CPA firm, has been monitoring the accuracy of his employees to determine whether the number of errors made by the employees is under statistical control. He sampled 30 accounts and examined them for errors. He found the total number of errors to be 220.

(i) Find the average number of errors. ________

 (ii) Find the centerline and the 3-sigma control limits for a c chart.

LCL = __________ Centerline =____________ UCL =___________

(iii) Using Minitab, generate the appropriate control chart for the data located in the worksheet labeled errors v21.mwx. Determine whether the process is in control.