need upper and lower limits

Refer to the table Factors for Computing Control Chart Limits (3 sigma for this problem. The overall average of a process you are attempting to monitor at Feryal Erhun Enterprises is 50 units. The average range is 4 units. The sample size you are using is n=5. a) What are the upper and lower control limits of a 3 sigma mean chart? Upper Control Limit (UCLX) = 52.308 units (round your response to three decimal places). Lower Control Limit (LCLx) = 47.692 units (round your response to three decimal places). b) What are the upper and lower control limits of the 3 sigma range chart? Upper Control Limit (UCLR) = units (round your response to two decimal places). i X Data Table Sample Size, n Lower Range, D3 0 0 2 3 4 0 0 5 6 Mean Factor, A2 1.880 1.023 0.729 0.577 0.483 0.419 0.373 0.337 0.308 0.266 Upper Range, D4 3.268 2.574 2.282 2.115 2.004 1.924 1.864 1.816 1.777 1.716 7 8 0 0.076 0.136 0.184 0.223 0.284 9 10 12 Print Done