Control limits

cnppmp's picture

C...

Normmaly or traditionally the Control chart would have UCL and LCL at 3 Sigma level. Universally followed.

Regards

CN Patil

Yes, I too answered as C. But as per key it is B(Farndales)

 

Yes, it is B: 3 Sigma in both directions.

--> 2 * 3 Sigma = 6 Sigma

cnppmp's picture

I think I have read the question incorrectly..it is talking about very tight controls...in that case it should be 6 sigma UCL & LCL.

Regards

 

CN Patil

I'm sorry but I disagree: The question is regarding the traditional limits and not regarding the "very tight process control". Therefore the basis for the calculation is 3 sigma.

--> The distance from the mean to th UCL is 3 sigma.

--> The distance from the mean to the LCL is -3 sigma.

 

The question now asks for the distance between LCL and UCL: This is 3 sigma + 3 sigma = 6 sigma.

Regards

Martin

 

jvleminc's picture

Tricky question, but I think B too (2*3 = 6) .