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Cpk 99.99 on charts & raw data

Discussion in 'SPC - Statistical Process Control' started by SPCgeek, Dec 22, 2020.

  1. SPCgeek

    SPCgeek New Member

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    Hi, I have a question:
    What is the reason for Cpk 99.99 on SPC charts? I assumed this happened due to no variation in readings taken. If there is no variation in the readings taken, then Cpk has to be infinity, since the standard deviation is zero.
    Another scenario is, there are difference found in Cpk values from different source of data. When the raw data is extracted for a particular process, the Cpk is showing 99.99. However when refer back to the chart, the chart is displaying a different & sensible value, like 2.50, etc.

    I have been searching the answer for days but yet to figure this out. Kindly help. Thanks.
     
  2. Gejmet

    Gejmet Member

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    Hi,

    Can you send the data over, impossible for anyone to answer really without looking at what you have.

    Thanks
     
  3. Bev D

    Bev D Moderator Staff Member

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    You would have to post the data for us to analyze.
     

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