• @shar6580 Double check the correctness of your assumptions. The only assumption for normality is in the residuals. There is no normality assumption for the raw data. Save your efforts of all those transformations. 1 year, 6 months ago

  • As for the second link the following commentary from their site

    “Consider the two regression models, and their residuals plots, shown here:

    The (lower) plots show the residuals for each model (the residuals are the errors between the regression lines and the actual data points). It can be seen that:

    1) The residuals for the ‘good’ reg…[Read more]

  • Well, the best I can tell you is what I said in my first post – most of what you quoted is wrong.

    Specifically – to the points made on the first site:

    “There are four assumptions associated with a linear regression model:”

    Linearity: The relationship between X and the mean of Y is linear. ”

    Not true – see the reference I gave in the…[Read more]

  • It occurred to me your phrase “Homoscedasticity: The variance of residual is the same for any value of X.” could be interpreted as a short verbal summary of the paragraph I wrote concerning what to look for when running the residual analysis. If this is the case then the statement is true but I think it is far too brief and could easily mislead…[Read more]

  • I’m afraid most of what you have stated is wrong.

    My reference is Applied Regression Analysis 2nd Edition – Draper and Smith

    1. There are no restrictions on the distributions for either the X or the Y. The question of normality (or approximate normality) is one that is restricted to just the residuals.

    The variance of the residuals is…[Read more]

  • Are you doing an MSA for the variation or the mean of the material you tested? 1 year, 7 months ago

  • I guess my first question would be – where did you get a KPI of 120 books/hour? That amounts to a minimum of 1 book every 30 seconds.

    Given your description “The rate is picking 120 units (books) per hour. They use carts, and are guided through the warehouse using tablets. What are some barriers that I should be looking for?” My personal…[Read more]

  • @lilianapereira Did you check our Case Studies section? You should find some Black Belt projects in there! 1 year, 7 months ago

  • No, the variability identified by your SPC chart is the ordinary variation of your process. If you try to use control limits that have nothing to do with your process all you will do is add to the process variation and make everything worse – this is known as over control.

    Usually a reference material is some kind of gold standard and you use…[Read more]

  • Michael Cyger's profile was updated 1 year, 7 months ago

  • Michael Cyger's profile was updated 1 year, 8 months ago

  • I would do it.  If they have something like a green belt–you’ll learn more. 1 year, 8 months ago

  • observation is a fantastic tool. 1 year, 9 months ago

  • Because, the contrast (or contrasts) that make the AxB interaction significant may not be the set of contrasts tested by just focusing on comparisons with a control.

    As for your recommendation – if your design matrix is such that the 0 setting for either A or B really means a complete absence of either A or B and not a case of A or B being at…[Read more]

  • No, the two methods do not show different results – the issue is you are not making the proper comparisons.

    In the regression you found the AxB interaction to be significant.

    In the test for group differences you chose to run a comparison against the control – this isn’t what you want to do.

    There are 4 combinations that comprise the AxB…[Read more]

  • I was looking at your data set again this evening and it occurred to me if you look at the data for count and count2 there is major difference between the two columns.  If count and count2 represent the results of a design and a full replication (I doubt this since the total counts are the same for both count and count2 but bear with me) of the 2…[Read more]

  • To your first modification of the 2**2 factorial design.  What you said you were doing and what you did are two entirely different things.  If you are going to set C = (0,0) and D = (1,1)  where the combinations are for A and B for those particular experiments then the actual design is:


    What you have done is this:


    This is just a standard ma…[Read more]

  • @flamepoop1120 This looks like a homework problem. Although the iSixSigma audience can be extremely helpful, they are not here to do your work for you.

    What do YOU think? Are you having trouble getting started? Where are you getting tripped up?

    The more specific you are — and the more of your own thinking you provide — the more likely you are…[Read more]

  • @miparent Have you seen this article? PepsiCo turns to Minecraft, moving virtual training away from ‘Zoom fatigue’ | HR Dive — 1 year, 10 months ago

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