Hello,

Can you please help me understand the following scenarios of a control chart:

1. If the value falls on the UCL (upper control limit) or LCL(lower control limit), (not above or below), is it considered to be "out of control"

2. If there are < 7 clustered points, above or below mean and within the UCL and LCL, is it considered "normal".  

3. What is an example of system being "out of control" or "needs caliberation" or "adjustment"

4. Above the mean and below the UCL or above LCL, is it considered to be +/- 3 sigma.

5. Is UCL and LCL also referred as specification limits. 

6. In oliver Lehmann questions for one of the control chart (No.3 of 75 questions), the choice is 'A special cause should be investigated, the process should be adjusted".

I dont understand this and also 9 points fall between mean and LCL.  It is difficult to find if 7 points are clustered to apply rule of 7, to determine if the process is out of control

If we can have answers to this, I guess we can answer all control chart PMP questions.

thank you

LK