iSixSigma

Lee

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  • Lee replied to the topic Xbar and R Charts in the forum General 10 years, 11 months ago

    You wrote …”It either means that there was a big coincidence or the measurement device may not have good enough resolution.”.  Other possibilities are that someone improved the process ….  or that persons are rounding values prior to making the log entry.

  • Lee replied to the topic Xbar and R Charts in the forum General 10 years, 11 months ago

    Let the experts weigh in too, but my 3 cents worth (2 cents, adjusted for inflation effects):
    PC charts are not designed to just detect unusually poor situations, but rather they are to detect unusual deviations.  Example: Weight per specs is 10 grams, SPC chart has UCL =12 grams, LCL=11 grams.  A reading of 10.5 grams  might save you money, an…[Read more]

  • Found the technique of what I wanted.  Each unit has a different variable name for the load, and each unit for which the load is not applicable has the load set to zero.  That forces the coefficient on Time to be the same in all units and each unit then comes up with a different coefficient on Load.
    Thanks for the new perspective that started br…[Read more]

  • Let me try again, sans fat fingers ;)
    Thanks for the reply.   In the stepwise regression (or regular) MiniTab is not producing a warning about the squared time, but it is nice to know about how to sidestep that issue via normalization.
    Now, is it possible to have the coefficient of the Load to be different, i.e., what I am getting is
    Temp= c…[Read more]

  • Tnaks for the reply.   In the stepwise regression (or regular) MiniTab is not producing a warning about the squared time, but it is nice to know about how to sidestep that issue via normalization.
    Now, is it ossible to have the coefficient of the Load to be different, .e., what I am getting is
     

  • Lee replied to the topic Reference Books in the forum General 10 years, 11 months ago

    I presume you mean Juran’s Quality Handbook rather than Juran’s Quality Control Handbook.  Correct?

  • Lee replied to the topic Reference Books in the forum General 10 years, 11 months ago

    Does anyone know of a way to conduct a poll on this site, even if via another party?
     
    We have quite a few suggestions thus far, and the time is approaching to conduct a survey based on the nominations that would help ferret out the top 5.  Likely the survey should consider if a person has not use/has never heard of a book listed, and co…[Read more]

  • Lee replied to the topic Reference Books in the forum General 10 years, 11 months ago

    Your pount that “…reference books are generally dry material that may not instill the passion …” is well taken.   Perhaps Phase II of this effort.
     
    Thanks for contributing to the list.

  • Lee replied to the topic Reference Books in the forum General 10 years, 11 months ago

    Thanks for the reply Robert.  I agree that a good part of our jobs is to be proficient in statistics – and smart enough to REALLY simplify it to those non-SS types we interact with.
    Regarding books at home – I keep what ends up to be most of my books at home due to limited work space & a culture here that does not encourage looking up stuff in b…[Read more]

  • Lee replied to the topic Reference Books in the forum General 10 years, 11 months ago

    Pardon my lack of rigor.  Yes, more precisely:
               the most used books is a function of a person’s job field, certification level, experience level (measured as years or by projects completed?), current type of projects worked, source of initial training (the books initially exposed to are likely to be the ones most referenced later), pers…[Read more]

  • Lee replied to the topic Reference Books in the forum General 10 years, 11 months ago

    Looks like we have a diversity of opinions (no surprise there).  Is there a way on this forum to list say 10 books and then have a poll run on the top 5?
    My vision is that the end point would be that newer persons could start with a library of those good books, and when posting responses that references would be to those books whenever…[Read more]

  • Lee replied to the topic Reference Books in the forum General 10 years, 11 months ago

    FWIW, I keep Implementing Six Sigma – Breyfogle here at work, but others at home (the other books are book I paid for)

  • A normally distributed data set will not necessarily produce a nice straight line.  In the past someone on this forum suggested that I generate “a bunch” of data sets that are normally distributed, each with about the number of data points I expected for the application I was tackling.  Then let Excel plot each of them.  Do that to get a feel of h…[Read more]

  • I could not find the data either, at least not through the time I got tired of searching.  I considered that the data was likely removed on some update of their web site.
    I considered just getting a large bag and giving it to my grandsons to sort by color.  Certainly that is sampling, but a sample of one large bag is better than ignorance (…[Read more]

  • Lee replied to the topic Formula for D2 constant in the forum General 11 years ago

    I’d like a copy of the spreadsheet too.  ealanni(at)windstream(dot)net.
    Now a question:  To keep life simple on the production floor, I almost always (40 or 50 instances) have a sample size of 5.  In one or two instances a sample size of 10.   Because of the desire to keep the sample size small enough to keep things simple I do not need D2 valu…[Read more]

  • Lee replied to the topic Opportunities in the forum General 11 years ago

    You said “… or changing our supplier to someone who will give us 10 free harnesses for every one we receive defective.”  Once I had a similar delima, so in contract negotiations we got the manufacturer to be boasting about how defect free his product was.  Then, we reinforced their stance by saying that they could offer to increase their wa…[Read more]

  • Lee replied to the topic pH Normally Distributed? in the forum General 11 years ago

    Thanks, that also explains why the measured pH for some mixtures have a standard deviation that is a lot wider than for other mixtures.

  • Lee replied to the topic pH Normally Distributed? in the forum General 11 years ago

    Thanks, I’ll seek out a chemist.  I had thought that for a given mixture that the distribution would be more dependent on the pH meter response characteristics and the stability of the mixing process — and somehow recognize that the meter readings are based on a log scale but that the process variations are (presumably) something other than a log scale.

  • Lee replied to the topic Johnson Transformation…..help in the forum General 11 years ago

    1.  Good basic approach you use, that normality is checked before generating non-meaningful statistics.
    2.  I do not consider myself adequate t respond to the Johnson transformation aspect of tour query, but I can respond this way:  It is likely that you can find some sort of standard transformation that makes the data look normal … but the bur…[Read more]

  • Lee replied to the topic Equations without Regression? in the forum General 11 years ago

    Thanks for the reply — I was thinking that there was another whole system (other than regression) that I could not recall.
    In my case the uncertainity in the recorded temperature is about the same as the uncertainity that the variation in time would also cause, so I wanted to be a tad bit more cautious in the analysis before I went on.  I have…[Read more]

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