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dull but serious maffs question

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    dull but serious maffs question

    Anyone tell me what the mathematical formula is to generate a random number that follows a normal distribution given:

    Have RND function that generates evenly distributed values.
    Have basic math function like log, sin, sqrt, exp etc.

    I want to generate random heights, weights, shoe sizes with the values following the expected normal dist of mostly 5'9" with a few tall gits and a few short arses etc.

    Not expecting you rabble to be any use whatsoever.

    #2
    Is the answer 12 ?

    No wait ..................13 ?
    I don't know my arse from an hole in the ground

    Comment


      #3
      Try Box-Muller algorithm - do a google for numerical recipes for the code to do this.

      Comment


        #4
        Originally posted by DimPrawn
        Anyone tell me what the mathematical formula is to generate a random number that follows a normal distribution given:

        Have RND function that generates evenly distributed values.
        Have basic math function like log, sin, sqrt, exp etc.

        I want to generate random heights, weights, shoe sizes with the values following the expected normal dist of mostly 5'9" with a few tall gits and a few short arses etc.

        Not expecting you rabble to be any use whatsoever.
        See http://www.taygeta.com/random/gaussian.html
        Work in the public sector? Read the IR35 FAQ here

        Comment


          #5
          Actually we are probably the best people to generate random answers...

          The problem is when you try to set paramaters...
          Vieze Oude Man

          Comment


            #6
            Originally posted by DimPrawn
            Not expecting you rabble to be any use whatsoever.
            Well it seems that I can google better than you at least:

            "The most important and useful member of the family of normal curves is the one having a mean of 0 and a standard deviation of 1. This curve is called the "standard normal curve" and has the equation y = (1/(2)) e(-1/2)x2."

            Not sure how that actually helps you?

            tim

            Comment


              #7
              Originally posted by DimPrawn
              Anyone tell me what the mathematical formula is to generate a random number that follows a normal distribution given:

              Have RND function that generates evenly distributed values.
              Have basic math function like log, sin, sqrt, exp etc.

              I want to generate random heights, weights, shoe sizes with the values following the expected normal dist of mostly 5'9" with a few tall gits and a few short arses etc.

              Not expecting you rabble to be any use whatsoever.
              find out the mean height of adults

              say 170 (+-) SD say 20cm

              generate any random number from 0-1

              multiply mean by SD

              mirror the positive section of the bell curve with negatives
              Last edited by Bagpuss; 24 October 2005, 15:23.
              The court heard Darren Upton had written a letter to Judge Sally Cahill QC saying he wasn’t “a typical inmate of prison”.

              But the judge said: “That simply demonstrates your arrogance continues. You are typical. Inmates of prison are people who are dishonest. You are a thoroughly dishonestly man motivated by your own selfish greed.”

              Comment


                #8
                Wait a minute....

                It's a trick question isn't it ?
                I don't know my arse from an hole in the ground

                Comment


                  #9
                  Its quite simple really...

                  Use the random number (between 0 and 1) and

                  sample from normal disb. = Sum of 12 Rnd Numbers - 6

                  I'm alright Jack

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