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How UAL,UWL,LWL,LAL is calculated

former_member494495
Active Contributor
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Hi Friends,

How Upper action limit, Upper Warning Limit, Lower warning Limit, Lower Action Limit is calculated from MEAN (centerline) ?

Thanks

Accepted Solutions (1)

Accepted Solutions (1)

Former Member
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check following links

this may help you

http://books.google.co.in/books?id=jsLg5EIagcEC&pg=PA55&lpg=PA55&dq=Upperactionlimit,UpperWarning+Limit,&source=bl&ots=nv4hFc_mOa&sig=j3-Rr9A8EKjCNEBMkgouNyDvypQ&hl=mr&ei=8A7mTeKlGYu-vgOksLDjCg&sa=X&oi=book_result&ct=result&resnum=3&ved=0CCMQ6AEwAg#v=onepage&q=Upper%20action%20limit%2C%20Upper%20Warning%20Limit%2C&f=false

http://www.cimt.plymouth.ac.uk/projects/mepres/alevel/fstats_ch8.pdf

former_member494495
Active Contributor
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Hi,

Theoretical ok.

I need to know in SAP the following values entered in the Define control charts is used for calculation ?

Numeric parameters

Parameter1 0.995000 Distribution function at the upper action limit

Parameter2 0.975000 Distribution function at the upper warning limit

Parameter3 0.025000 Distribution function at the lower warning limit

Parameter4 0.005000 Distribution function at the lower action limit

former_member494495
Active Contributor
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Sujit Gujar

My client want to know how it is calculated in sap

Former Member
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I gues you have the mean value * std deviation ready with you. So try thye following formula:

UWL = mean+2u03C3/u221An

LWL = mean-2u03C3/u221An

UAL = mean+3u03C3/u221An

LAL = mean-3u03C3/u221An

u03C3 is std. deviation and n no of samples

See if these formulas return the same value as is being shown in SAP. Or you can go through the following book [http://books.google.co.in/books?id=JLm1r6rUAdcC&pg=PA109&lpg=PA109&dq=whatisupperactionlimit&source=bl&ots=I-Z4c7AQfg&sig=Bftjs8FWzngpPamlTOFQ0issF1o&hl=en&ei=cLDoTdWKMoy0rAfi-Jx9&sa=X&oi=book_result&ct=result&resnum=6&ved=0CDgQ6AEwBQ#v=onepage&q=what%20is%20upper%20action%20limit&f=false].

SAP uses usual formulas for calculation, nothing extra. So any statistician or good mathematician will be able to make you understand the limit calculations.

former_member494495
Active Contributor
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Hi,

In sap i changed the above numeric parameter 1 from 0.995 to 0.95 then the warning limit and action limit is changing.

So it is calculated by some other formula.

Former Member
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Hi

Have yo consulte with any statistician or gone through the link I provided? There might be no. of conditions that apply to a particular formula and its limits selection. At the end its simply statistical formula, for both legacy and SAP

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