• I’ve been giving your problem some thought and I can’t think of any single statistic that will capture consistency both with respect to stability of system variability and constancy of trending.  The issue you are facing is that of an evolution of both variation and trend across time. As far as I know, if time is involved you will have to take it…[Read more]

  • Based on your post there not only does not seem to be any need for a 1-10 rating but, it doesn’t sound like your colleague has any idea of how to build a meaningful 1-10 rating scale that would be of any value to you.

    What your post does suggest is you have some understanding of why coils are rejected.  For example, you mentioned dark surface on…[Read more]

  • The question you are asking is one of a comparison of two proportions.  Specifically you want to know if the difference between 100% and 82.5% is statistically significant for a sample of 315.

    The key is to recognize that the proportions are 315/315 and 260/315.  In other words, with a baseline of 315 in both cases we have a situation where t…[Read more]

  • The short answer to you second post is: there’s nothing like that out there.

    Let’s take another look at what you are asking:

    You said: “I was looking for some current affairs metric that can tell me if something like the historical average growth rate will continue or if a certain ratio will stay stable in the future.”

    If a measurement such as…[Read more]

  • I might be missing something but, as written, your post appears to be expressing two different requirements.  You say you want to predict variation, specifically predict variation trending, however, the examples you give have nothing to do with prediction.  Both both CD and CV are strictly summations of current affairs – they don’t have any p…[Read more]

  • ….an additional thought.  I was going over the case study and looking at the data set for Case #2 and it occurred to me that, if you want to, you can use that data set as a starting point for what would amount to an excellent self teaching exercise.

    In the attachment I’ve rearranged the data to make the composite nature of the design more…[Read more]

  • The way you would determine the minimum and maximum settings shown on page 28 would be to take the regression models for collapse and burst pressure and put them in an optimizing program and run them.  I don’t know Minitab but I do know it has such an option.

    The problem is the author has not provided the models he generated using the data.  S…[Read more]

  • @imrovement101 We have a whole healthcare section with almost 150 articles that might help:

      1 week, 6 days ago

    • Homework Problem–I didn’t say it was impossible to get a response. I said it was unlikely. In this instance, Robert was generous and replied before I had an opportunity to post and suggest the original poster share their opinion/thought processes first.
    • Bernoulli Distribution–You clearly state your opinion before asking others for…

    [Read more]

  • is this a question? :) 2 weeks ago

  • I might be missing something but my understanding of the scenario you described is as follows:

    a. Quality team takes a 10% sample of the total output.  With a total output of 1000 this becomes a sample of 100.

    b. Quality team does a 100% inspection of the 100 samples and finds 10 defects in that sample.  Therefore, their claim, based on the e…[Read more]

  • @fausto.galetto If you lead with what you think and why/why not, you may get a reply. Otherwise, you likely won’t. It’s that simple. 2 weeks, 1 day ago

  • @fausto.galetto You know how the forum works! :) What do YOU think? Why/why not? The iSixSigma audience isn’t here to do your work for you. 2 weeks, 2 days ago

  • Hope you’re staying safe @MBBinWI 2 weeks, 6 days ago

  • If you are going to re-sample the internal audit sample then the short answer is the sample size is no longer 100 it is 110 and 11/110 = 90%. Another way to look at this is you have a sample of 100 – you find 10 defects in that sample.  You dump everything back in the bin and run a re-sample of the same population taking 10 samples and finding 1…[Read more]

  • Always attack the constraint IF you need more capacity or the possibility to assign labor to other “lines” or processes so overall labor cost drops because fewer shifts or hours are used to produce the same amount of product.

    However, defects may have a higher cost impact than lost sales–heresy, I know, that sales can’t sell everything made if…[Read more]


    This sounds like a homework problem but I’m done with my remote work and I’m not really ready to start back in on my latest book read so…

    7 = Xbar1 = the average over 153 days.


    7 x 153 = the sum of the individual measures for the 153 day period (remember: the sum of individual measures/153 = average = 7)

    12 = the desired average…[Read more]

  • @leavor Minitab has excellent technical support. Have you checked with them directly? I have notified them of this post in the meantime. 1 month, 1 week ago

  • @Andy-Parr That’s the second article I specifically linked to above. :) 1 month, 1 week ago

  • To do things like this you really need to spend the money, purchase some good books on experimental design, and read them and keep them close by as a reference.

    The two I would recommend are:

    1. Understanding Industrial Designed Experiments by Schmidt and Launsby

    2. The Design and Analysis of Industrial Experiments by Davies

    To your point -…[Read more]

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