Thread: Math wiz help neede..

  1. #1
    Its not rocket science vasanth's Avatar
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    Math wiz help neede..

    Ok I know how to calculate the Standard Deviation of say 10 given values....... But can some on etell mehow i can calculate the reverse...

    Say i Have a standard devaition of 0.316 now I would like to generate say 10 values that give this deviation......

    Thanx for any help...

  2. #2
    Registered User axon's Avatar
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    I doubt that it is possible; the same standard deviation could be obtained from an infinity of sets of ten numbers...you will never get the exact 10 that this deviation was used for. There might be a generalization about these infinite number of sets however... you need some more info vasanth.

    I might be wrong, but right know I don't see a way - but I have statistics today and I just might ask my prof!

    some entropy with that sink? entropysink.com

    there are two cardinal sins from which all others spring: Impatience and Laziness. - franz kafka

  3. #3
    Its not rocket science vasanth's Avatar
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    well its fine as long as I get any 10 numbers within a given range that gives the same deviation...

    I dont care what those numbers are as long as they satisfy the deviation..

  4. #4
    Registered User axon's Avatar
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    >>I dont care what those numbers are as long as they satisfy the deviation..<<

    ahh, well that changes things a bit...when I get home today I'll try to work something out.

    some entropy with that sink? entropysink.com

    there are two cardinal sins from which all others spring: Impatience and Laziness. - franz kafka

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    Well, standard deviation is the square root of the variance, so I suppose you could plug in variables and try to solve for it? First off you'd have to find a mean.

    (x-mean)'+(y-mean)'+(z-mean)'
    --------------------------------------- = variance (' is "squared")
    3

    Trying to get 10 or so numbers crunced out of that is beyond me.

    You do know that falsifying data is frowned upon, don't you?

  6. #6
    Its not rocket science vasanth's Avatar
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    Quote Originally Posted by exluddite
    You do know that falsifying data is frowned upon, don't you?
    lol.. actually I need this data to simulate phone calls...(acually call holding time).. and the input given by the user is just the deviation and I need to do the rest...

    Hope some one here can come up with a solution on how to calculate it..

    thanx in advance..

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