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Control Charts Notations

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  • #53599

    Anonymous
    Guest

    Hi everybody

    Do you know why in control charts calculations :

    – c4 is noted… c4 (what means the “c” and what means the 4)?

    – d2 is noted…. d2 (what means the “d” and what means the 2)?

    – d3 is noted…. d3 (what means the “d” and what means the 3)?

    – d4 is noted…. d4 (what means the “d” and what means the 4)?

    – A2 is noted…. A2 (what means the “A” and what means the 2)?

    – B3 is noted…. B6 (what means the “B” and what means the 3)?

    – B4 is noted…. B4 (what means the “B” and what means the 4)?

    – B5 is noted…. B5 (what means the “B” and what means the 5)?

    – B6 is noted…. B6 (what means the “B” and what means the 6)?

    I will have a class about SPC in a few month in my company. I have to make the mathematical proof of this coefficient (this point is ok) but i’m sure that my student will ask me where these notations comes from and i did not found any informations about it….

    Thanks for your help

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    #190807

    Robert Butler
    Participant

    You need to get a good book on quality control and do some reading. One possibility is Quality Control and Industrial Statistics – Duncan – 4th Edition – Table M in the back lists all of them, their mathematical definitions, and it points you to the source document.

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    #190854

    Rohatgi
    Participant

    These are just notations used to represent sample size dependant constants.
    Natural choice is Alphabets A,B,C, D etc. with 1,2,3,4…as subscripts.

    There is no other meaning to it. Just as R is used to represent Range, MR is used to represent Moving Range

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    #190859

    SOS
    Member

    Hi

    You shall refer “Industrial Statistics” books by Duncan.

    Any other doubts please feel free to ask.

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