Recent content by obh

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    Paired vs unpaired t test

    When you use dependent samples you use paired t. For example you compare the same person before treatment and after treatment. Can you paste some data for better understanding?
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    Correlation

    Correct :), edge examples help to understand
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    Correlation

    This is good. I prefer going to the edge. You should try(1,2,3,4,5,6) and(-3,-2,-1,0,1,2) And compare it to (1,2,3,4,5,6) and (7,8,9,10,11,12)
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    Correlation

    I can answer your question, instead I will suggest a test. Build 2 perfect correlate set of data, one only positive and one half positive and half negative and see what result correlation you get...
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    Test & Control File Selection - Help

    1- it's not bad practice to sort on the identified key variable and select the test records using every 2nd record and that using Stratified Sampling is however a better method? I thought you mean taking totally randomly files every second one without sorting. sorting probably will be good as...
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    how to automatically repeat the same analysis

    Hi Css, I glad I could help you :) Of course, the page is not a substituted to SPSS or R ...but it can do the job in your case and many other cases, hopefully easily... Actually, I didn't notice it was an SPSS question ... I tested it successfully in google chrome with 3 X columns and 50 Y...
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    Test & Control File Selection - Help

    "Hi obh, yes i believe you are referring to stratified random samples which is one of my options. As to why every second record - I am however the whole prospect file into two 50% files therefore sorting on my key variable (say age) and taking every 2nd (even) record as the test and every odd...
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    how to automatically repeat the same analysis

    Hi css, Please check the "Coefficient table", "Stand Coeff" column.
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    Test & Control File Selection - Help

    I don't understand why every second record? A simple example (hopefully I understand you correctly): Let assume your main variable is color: 40% red, 60%blue. You want to take a sample of 10% and change the message in this sample. (to check if the message change will influence Y) If instead...
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    Test & Control File Selection - Help

    If you know the standard deviation from the entire population you should use z-test. if you calculate the standard deviation only from the sample you should use the t-test. Before ...can you plan your sample to have a similar key variable, instead of taking it randomly and then test it?
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    Test & Control File Selection - Help

    Generally, it is better to use the t-test if you don't know the population standard deviation. t limit to Z when n limit infinity, and when n>30 z will also give you a reasonable result. but I assume it is relevant to the time people used tables instead of computers ... to reduce the standard...
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    Logistic regression

    Hi Arn, Please don't say that about yourself :( If you paste your data in the following link you will have a bit better explanation: http://www.statskingdom.com/420logistic_regression.html If you still have a specific question please let me know
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    how to automatically repeat the same analysis

    Okay, It should not be a problem.
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    how to automatically repeat the same analysis

    Hi Css, I assume that you want to standardized the data before performing the regression.? It should not be a problem. Do you need both standardize and not standardized? I will check tomorrow. Please check my answer tomorrow :)
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    how to automatically repeat the same analysis

    Coefficients are there (coeff in the second table) . Generally, you need to check in "Residuals Table" or/and " ANOVA Table" or/and... to get more data. I assume it should be okay now. If still not okay, can you please show an example of how you like it to be? (includes the residuals) and I...