iSixSigma

MrKid

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  • #158380

    MrKid
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    Allen,
    If you have a one-sided lower spec, then Cpk=(Xbar-LSL)/3s.
     

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    #138695

    MrKid
    Participant

    The certification will help your resume get past the HR recruiter and into the hands of the hiring manager, which is one of your primary goals in applying for a job: to make it through the screening process.
    The certification will probably not get you the job.  Your ability to sell yourself and describe what you can do to help the hiring manager will do that.  If a manager is hiring based solely on a certificate, he/she is a fool, because all certificates are not created equal.
    The certification will not directly make you better at performing the job.  Your knowledge and experience will do that.  A good certification program will acknowledge that you have displayed the skills (change management, project management, problem solving, leadership), but again, all certs are not created equal.

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    #137052

    MrKid
    Participant

    If you are reacting to an out-of-spec result that is within control limits (I assume that when you say reacting, you are talking about making some process adjustment) then you are treating common cause variation as special cause variation.  The danger is in overadjustment.  If your output is below spec and you make some adjustment to bring it up, due to common cause variation you will eventually find yourself above the upper spec (and wanting to make the adjustment back to where you were before). 
    Are you really gaining anything by making these adjustments?  Is the process just as likely to come back into spec on its own without making the adjustment?  If you are making all of these adjustments, is the process really stable?  Do you know what the common cause variation is with the process if you don’t make any adjustments?  We have had that experience, where we didn’t really know what the common cause variation was because a special cause (operator adjusts the machine) was interfering with the data.
    Is there an understanding of the critical inputs and how they affect the outputs?  Are they being addressed?
     

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    #80170

    MrKid
    Participant

    Interesting question.  We are usually working in the opposite direction, converting process capability into dpm or dpmo to put it in terms that non-statistically minded people can wrap their minds around.
    Anyway, here is an equation that I was given, but have never really used for Cp.
    Cp=(.8406+sqrt(29.37-2.271+ln(dpm)))/3
    I’m guessing this is an approximation of the Z tables.

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