iSixSigma

Remi

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  • Remi replied to the topic Maximum Likelihood Estimator in the forum General 12 years ago

    Hai marife,
    you don’t.
    For deciding which distribution fits best with your data you use the p-values that you get from that same investigation (H0: My data distribution is equal to the tested distribution). And in general it is the same as with Normality test: if the p-value is high your data fits the distribution well; if the p-value is low it…[Read more]

  • Remi replied to the topic exclude factors after DOE in the forum General 12 years ago

    Hai K,
    Remark: since you didn’t include centerpoints you can not check if the linear model is correct (maybe a non-linear model would be more correct).
    My assumption is that for each run you performed a break test and measured the load value at the point of breaking. 
    Due to physics we can (=I) assume that for the no-breaks the load value of…[Read more]

  • Remi replied to the topic ANOVA ? in the forum General 12 years ago

    Hai UKB,
    Question: are the intermediate weights important for you or the customer? If not then the standard paired test is applicable. You could also perform the paired test for each pair of months (1,n) for n=2..6 in order to see on which month the average weight loss is significant.
    But remember: with statistics you only will prove that the…[Read more]

  • Remi replied to the topic Standard Error in the forum General 12 years ago

    Hai Danial,
    like Darth said: what are you talking about? In your message there is a contradiction: Paired comparison can not be done with different sample sizes. Look up the definition of paired comparison.
    I can guess that you might have meant that you have several subgroups of paired data and the subgroups have different sizes and different…[Read more]

  • Remi replied to the topic Analysis Help in the forum General 12 years ago

    Hai MB,
    first of all make all the pictures/graphs (create extra Y column with 0/1 for good/bad for Matrixplot) to get a feeling for the data. Don’t forget to use time as an extra X.Decide which data you want to analyse based on the info from these pictures. Check if the data of the X’s cover their possible values well (i.e. sample is…[Read more]

  • Remi replied to the topic Normality test and robustness in the forum Europe 12 years ago

    Hai Ajay,
    there is no reason that a forecast should be normal distributed. And analysing a forcast on its own makes no sense to me. Why would you want to do that?For Forecast Robustness: look at Prediction Interval and Confidence Interval that you get from the regression analysis. They give you info about robustness.
    The general answer is…[Read more]

  • Remi replied to the topic Too many zeroes in the forum Software/IT 12 years ago

    Hai Sri,
    No problem; I am not an IT expert so don’t know what CMMI is.CTQ can be translated into ‘variable that is important to measure’. It generally is a parameter of which your customer has decided that it is important to know what it is doing.
    Explanation by example.
    I want to measure Delays.Each time there is a delay I record the # of…[Read more]

  • Remi replied to the topic Range vs Stdev in the forum General 12 years ago

    Tom,
    It is the other way round.
    Whenever taking an S (st.dev of Sample) the Confidence Interval around that S is large if the sample size n is small.
    A trade-offs between ‘what is needed (based on statistical calculations)’ and ‘what is possible (based on expense and reasonability decisions)’ leads to recommendations on n that often are r[Read more]

  • Remi replied to the topic how to interprate in the forum General 12 years ago

    fara
    this is the end of a chi-square test which gave as outcome a chi-square value of 2.258 and degree of freedoms equal to 3 (so you had 1 column with 4 entries OR 1 row with 4 entries) and the calculated p-vlaue = 0.521 (sig stands for significance level).
    Look upo CHi-squared test or proportion testing to see what it all means.
    Remi

  • Remi replied to the topic Chi-Square in Excel in the forum General 12 years ago

    Hai Jeff,
    Chi-sq value = SUM over all cells of {(the square of (observed value – expected value)) divided by (expected value)}.You can see this also in the Help when you choose the CHITEST function in XL (click on fx-button and then on ‘help with this function’).
    But for this you need the original data.
    If your input is p-value and df use the…[Read more]

  • Hai Arturo.
    Such a test only will divide your products into 2 groups: passed (1) and failed (0). The test is not very good for evaluating your products and process behaviour because you only can analyse groups of samples (how many 0’1 and 1’s you have over time).
    I recommend you to change the test in the following (easy?) way:Put a stress of…[Read more]

  • Remi replied to the topic processes capability in the forum General 12 years, 1 month ago

    Zubdah:
    you are thinking wrong and missing the point of what Cp(k) is intended to do.Cp= “Voice of Customer” / “Voice of process”.In order to get a value you fill in USL-LSL for “Voice of Customer” and fill in 6S for “Voice of Process”.
    If you choose USL = Mu +2S then you choose the specs based on “Voice of the Process”. THIS IS WRONG!As a…[Read more]

  • Remi replied to the topic Mann-Whitney Test in the forum General 12 years, 2 months ago

    Hai Fairy,
    something strange in your output: the point estimate is not inside the CI. And the Ci is inverted (3,-26) would normally be written as (-26,3) (= all real values bigger than -26 and smaller than 3)
    Explanation output: (can be found in any Minitab output by clicking in the output and then clicking on the Special help (next to the…[Read more]

  • Remi replied to the topic Data Points in the forum General 12 years, 2 months ago

    Lynn,
    you can also use Dotplot: it shows individual points.Use Boxplot if you are only interested in potential outliers/flyers.Use time-series graph if you want the order of data to be included. Use the I-MR controlchart if you want info about control.
    Remi

  • Remi replied to the topic correlation and regression in the forum Europe 12 years, 2 months ago

    Hai Jody,
    Ah now things are clearer.
    # data appears to be large enough. In the Scatterplot you should see a point (#18) far away from the regression line.Maybe analysis is improved when this point is removed from the data. But this may only be done if you can find out why this point shows different behaviour than the other points.
    Both…[Read more]

  • Remi replied to the topic correlation and regression in the forum Europe 12 years, 2 months ago

    Hmm, Jody;
    If you mean that the Correlation disagrees with the Regression analysis, I think you must have made a mistake somewhere.
    If one has 2 columns of data in Minitab and performs Correlation (Stat => BasStat=>Corr) and Regression (Stat=> Regr=>Regr) one will get the same p-value (because essentially the same H0-analysis is done). And a…[Read more]

  • Remi replied to the topic Too many zeroes in the forum Software/IT 12 years, 2 months ago

    Hi ZH,
    see articles on G-control Chart (search Main page)
    Other option is: define 2 CTQ’s.
    CTQ1= % of non-zero’s over longer time period; and treat it as you would reject level (no USL, LB=T=0)CTQ2= count (or %) if >0 over the time/amount already chosen and analyse this as reject level.Both together give an indication of quality. Danger is in…[Read more]

  • Remi replied to the topic correlation and regression in the forum Europe 12 years, 2 months ago

    Hi jody,
    How do you know they are correlated? If from Data then the same data should give you a good Regression relation (mathematically true).If from Expertise then find out why the data does not correspond with what you know ‘has to be true’.Be aware that your way of data collection can kill any theoretical relations.
    Check data with Expertise…[Read more]

  • Hi James,
    if your measurement system is perfect:

    with Power=0.5 you need 11
    with Power =0.9 you need 26
    Minitab: Stat => Power&SampleSize => 2 proportions; fill in 0.5 and 0.1 (worst case) and Power.
    Remi

  • Remi replied to the topic Combination in the forum General 12 years, 3 months ago

    Hi Edward,
    Combine drugs with work and you will be replaced by your boss.
    Remi

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