A textile company monitors its process by counting the number of defects in the bolts of cloth it produces. To establish its control chart limits, a random sample of 20 bolts of cloth was selected and the average number of defect per bolt calculated. If the sample average was 25 defects per bolt, then the 3-sigma upper and lower control chart limits for this process would be
UCL = 20; LCL = 5
UCL = 45; LCL = 0
UCL = 40; LCL = 10
UCL = 25; LCL = 15