P
puck1263
So, I understand the concept of WITHIN (subgroup) standard deviation and BETWEEN (subgroup) standard deviation. Also that BETWEEN/WITHIN is root(within^2+between^2).
OVERALL is stdev of all measures.
Question 1:
Why is Overall stdev not equal to between/within? I don't understand.
Question 2:
I have a process improvement where WITHIN, BETWEEN, and WITHIN/BETWEEN stdev all went down (by quite a bit), but OVERALL went up. How can this be? Perhaps related to question 1.
OVERALL is stdev of all measures.
Question 1:
Why is Overall stdev not equal to between/within? I don't understand.
Question 2:
I have a process improvement where WITHIN, BETWEEN, and WITHIN/BETWEEN stdev all went down (by quite a bit), but OVERALL went up. How can this be? Perhaps related to question 1.