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  • Thai replied to the topic What about STATGRAPHICS ? in the forum General 15 years, 8 months ago

    I would tend to agree with Stan.  Stop trying to sell software.  At least admit that you are a sales rep for Statistica…

  • Thai replied to the topic Six Sigma haters in the forum General 15 years, 8 months ago

    The first article was Copyright 2001.  I guess 4 years later we can see the wisdom of their program through the fact that so many people can recognize the name of the philosophy…. what was that name again? PINK? POOP? PEEP?
    Kirk

  • Thai replied to the topic Defining an opportunity in the forum General 15 years, 9 months ago

    Hand slap across the back of the head felt and acknowledged. 

  • Thai replied to the topic Defining an opportunity in the forum General 15 years, 9 months ago

    CM,
    Why are you so worried about defining how many opportunities exist in a glass fab process to cause scratches.  Anytime something comes in contact with a piece of glass there is an opportunity for a scratch to occur.  I would concentrate on the proportion defective coming out of each step in the process.  Also try using a scatter plot to dete…[Read more]

  • Who is going to provide on-site mentoring of all the GB’s that are going to be trained?  Does your company have BB’s at the locations?  If so, get them involved in the GB development process.  
    Which ever route you take, in my opinion, the most important aspect of the training is to make sure that the people who are providing the training have…[Read more]

  • Thai replied to the topic why use higher p value? in the forum General 15 years, 9 months ago

    Niki,
    Although I come from a manufacturing background, and not research, I typically use a p-value of 0.1 when running a screening DOE.  On subsequent followup DOE’s I will then use a lower p-value (i.e. 0.05 or 0.01 depending on how much risk I am willing to take) for determination.
    Kirk

  • Thai replied to the topic Capability analysis in the forum General 15 years, 9 months ago

    and he said the sample size was 30.  There shouldn’t be an issue with sample size.

  • Thai replied to the topic Capability analysis in the forum General 15 years, 9 months ago

    That crossed my mind, but the question was asked from a pure graphical analysis point of view.  I am still not clear what Newbie is looking for.
    Kirk

  • Thai replied to the topic Capability analysis in the forum General 15 years, 9 months ago

    I guess I must be missing something in you question, but let me try again.  Normality of individual data points has nothing to do with sample size.  That being said, small sample sizes from normal distributions may appear to be non normal when looking at a histogram because of the small sample size, however if the underlying distribution is n…[Read more]

  • Thai replied to the topic Capability analysis in the forum General 15 years, 9 months ago

    Newbie,
    Although I am sure UFO will be predictable and call me an idiot, the issue you are seeing has nothing due to round off of the standard deviation.
    Minitab defaults to an Average Moving Range Method to calculate the within standard deviation.  This is given by the following equations:
    MRbar = (MRw +…+MRn)/(n-w+1) where
    n = number of…[Read more]

  • Thai replied to the topic Capability analysis in the forum General 15 years, 9 months ago

    OK,  I will review the theory behind calculating short and long term variance if you agree to go see someone about your obvious anger management issues.
     

  • Thai replied to the topic Capability analysis in the forum General 15 years, 9 months ago

    So what you are saying is that the difference between the Cp and Pp numbers can be based on the degrees of freedom resulting from the different methods used to approximate long term and short term standard deviations?
     

  • UFO,
    Thanks for the reference.  I won’t pretend that I am a statistician.  I am an engineer that looks for the practical use of statistics in process improvement activities.  So tell me other than to try and show how smart you are, where have you used a WS approximation in a practical situation?  Unlike many of the people you have been att…[Read more]

  • Thai replied to the topic Capability analysis in the forum General 15 years, 9 months ago

    Newbie,
    Right.  It is the Average Moving Range method that Minitab may use for within standard deviation.  Here is a link to a White Paper entitled “Formulas for Capability Analysis…” on the Minitab website that will describe this further…  http://www.minitab.com/support/answers/answer.aspx?ID=294
    As far as your second question is concer…[Read more]

  • Thai replied to the topic Capability analysis in the forum General 15 years, 9 months ago

    Newbie,
    Sorry, I misread your original question.  The issue you are seeing has nothing to do with the normality or time dependence.  The reason that the reported value for Cp is less than Pp (and the same with Cpk and Ppk) has to do with how the standard deviations are approximated.  Two different calculations are used to appoximate the within (s…[Read more]

  • Thai replied to the topic Capability analysis in the forum General 15 years, 9 months ago

    What limits are you using to calculate the Capabilities?  I agree, the data is normal and does not show any time dependence. 
    Kirk

  • Thai replied to the topic Capability analysis in the forum General 15 years, 9 months ago

    Is your data abnormal or is there some sort of autocorrelation present in your data?  This will cause the assumptions in calculations for Normally distributed process capabilitys to return incorrect results. 
    Kirk

  • UFO,
    OK, so you have proven you can perform a Google search and are able to find a formula to approximate degrees of freedom.
    Please tell us “idiotic wanna-be statitician(s) with self-generated delusions” your take on the Welch-Satterthwaite forumula and where you have used it in a practical situation.
    Kirk

  •  
    There is a TS16949 Requirement for MSA…

    7.6.1 Measurement system analysis

    Statistical studies shall be conducted to analyse the variation present in the results of each type of measuring and test equipment system.  This requirement shall apply to measurement systems referenced in the control plan.  The analytical methods and ac…[Read more]

  • I don’t believe there is a need for a specific award for Six Sigma Organizations.  The recognition comes through other means (i.e. Quality Surveys, market share, profits, stock prices).  This falls in the same line as certifications.  Anyone can get a certification.  The questions comes down to how effective are you.
    Kirk

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