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Re: AI-GEOSTATS: bounds of IK variograms

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  • Mario Rossi
    Jorg, that is correct. The variance of any binary variable (such as an indicator variable, 0s and 1s) is, by definition, p*(1-p), where p is the percentile
    Message 1 of 3 , Jun 16, 2003
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      Jorg, that is correct.

      The variance of any binary variable (such as an indicator variable, 0s and 1s) is, by definition, p*(1-p), where "p" is the percentile of the distribution.

      Therefore, the maximum possible variance of an indicator variable will be 0.25, when p=0.5; also, the variance as a function of the percentiles is a symmetrical curve, where p=10 has the same variance as p=90.

      The only comment is, that, strictly speaking and as you probably know, covariances and variograms are not always interchangeable.

      Cheers,


      Mario


      "Dilling,_J�rg" <Joerg.Dilling@...> wrote:
      dear all,

      i have performed indicator kriging with different thresholds (corresponding
      to 10th percentiles). is it correct that the variogram of each
      xth-percentile is bounded to:

      max cov = xth_percentile* (1-xth_percentile) ??

      e.g. max cov (30th perc.) = 0.21, max.cov (90th perc.) = 0.09


      thanks for comments

      regards
      j�rg

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      D - 95615 Markredwitz

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