A restaurant is improving its processes, and is currently focusing on the final bill presented to customers. The manager samples 50 bills per day for 12 days, and checks to see how many are incorrect using a z-value of 3. Is the billing process consistent (in other words, is it in control), or do special cause events appear to be present? What is the UCL? What is the LCL? You collect two more days of data, again sampling 50 bills per day, and add the results (11 incorrect bills on day 13 , and 9 on day 14 ) to the control chart. How many days are now outside the control limits? What is the UCL? What is the LCL? A restaurant is improving its processes, and is currently focusing on the final bill presented to customers. The manager samples 50 bills per day for 12 days, and checks to see how many are incorrect using a z-value of 3. Is the billing process consistent (in other words, is it in control), or do special cause events appear to be present? What is the UCL? What is the LCL? You collect two more days of data, again sampling 50 bills per day, and add the results (11 incorrect bills on day 13 , and 9 on day 14 ) to the control chart. How many days are now outside the control limits? What is the UCL? What is the LCL