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GRR Error vs. Disposition of Any One Item

Six Sigma – iSixSigma Forums General Forums Implementation GRR Error vs. Disposition of Any One Item

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  • #54599

    Lucas
    Participant

    After completion of a GRR, how exactly do I apply the data reported by MiniTab to come up with a +/- error for any measurement I may take?

    What about a specific part? What if I want to have a 99% confidence in my decision about a part which is 0.900″ not being 0.901″?
    If I want a 95% confidence in my disposition decision, where should I draw the decision line to reject? i.e. reject at 0.898″? to allow two sigma (GRR StDev = 0.0011) between my value measured and the specification limit?

    Can I say that there is 95% certainty any value I measure is within a floating window of 6*SD = 0.0068″? Or that there is 95% certainty any value I measure has an actual value that is not larger than 3*SD = 0.0034″ higher?

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    #196269

    Vyanktesh Kulkarni
    Guest

    Hi,
    1. Measurement error or uncertainty
    GRR analysis has given the STDEV of the measurement system as 0.0011. Hence any value measured using this system will be in between 3*0.0011 (0.0033). Pl check if this much variation is acceptable w.r.t tolerance specified.

    2. For acceptance or rejection of a sample
    The operating limits of the parameter can be set between USL – 3SD to LSL + 3SD

    Trust this helps.

    Regards

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