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Thread: "Normal" distribution or not?

  1. #1

    "Normal" distribution or not?




    Hello guys, congratulations for the forum, it's really great. I am an italian student of medicine and I'm starting to learn statistics matter couz I should plan a clinical trial. But, let's get back to us. I should analyze the weeks free of infections after administration of a drug compaired to placebo group. How can I understand if this variable is "normally" distributed or not? Hoping to be understood , best regards from italy....

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    Re: "Normal" distribution or not?

    Start by looking at histograms and QQ plots, then do a test of normality.

    http://en.wikipedia.org/wiki/Normali...quentist_tests

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    Re: "Normal" distribution or not?

    In medical literature i found a clinical trial quite similar to mine, and he used a wilcoxon test, so i should deduce it's not normal. But what do you suggest? should I check again if the variable is normal or could I trust in it? thank you for the speed

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    Re: "Normal" distribution or not?

    You should check yourself. Don't assume your data has the same properties as other data.

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    Re: "Normal" distribution or not?

    Quote Originally Posted by Stratovarcticas View Post
    In medical literature i found a clinical trial quite similar to mine, and he used a wilcoxon test, so i should deduce it's not normal. But what do you suggest? should I check again if the variable is normal or could I trust in it? thank you for the speed
    Just because somebody used a wilcoxon test doesn't mean the data wasn't normal. It could have been normal but they just didn't want to make that assumption for one reason or another.

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    Re: "Normal" distribution or not?


    thank you guys I really appreciate your help

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