Question 1. [Project Quality Management, Statistical Process Control Charts]

In a project, "Length" has been identified as a quality characteristic to be monitored by a process control chart. The quality characteristic is assumed to be Normally distributed. The following measurements from an experiment under control were obtained.

Item #	1	2	3	4	5	6	7	8	9	10	11	12
Length in Millimeters	321	305	317	302	302	304	318	308	315	316	320	316

Using the data, construct a simple process control chart. What is the "lower control limit", the "center line", and the "upper control limit" of the control chart? (Use Population Variance)

Chart	A	B	C	D	E
UCL (Upper Control Limit)	319	318	314	333	None of the above
CL (Center Line)	312	312	312	312
LCL (Lower Control Limit)	305	306	310	291