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89 results from messages in new_ai_geostats

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  • Dear Madam/Sir, I was wondering how the area under a gaussian distribution curve is 1 if the tails go off to infinite?, the area must be infinite unless some unless some approximation is made? Digby
    Digby Millikan Dec 23, 2005
  • Sorry, I should have been more specific, I meant the kriged estimates’ error distribution is normally distributed, with a variance of the kriging variance for input sample data with a normal distribution. Regards Digby
    Digby Millikan Nov 7, 2005
  • Dear list, If you had a set of blocks is it possible to add their kriging variances together, to get a standard error for the mine head grade, is this something that is done in practice or has been done in the past to estimate possible deviations from a kriged head grade? Digby
    Digby Millikan Nov 7, 2005
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  • I think if your data is normally distributed, your kriging variance is normally distributed. You will have higher kriging variances for sam ples which have higher variogram values Digby From: Feng Liu [mailto:asherliu@^$1] Sent: Wednesday, 2 November 2005 4:32 AM To: 'AI Geostats mailing list' Subject: [ai-geostats] Kriging Variance Dear List: Got two questions about Kriging...
    Digby Millikan Nov 7, 2005
  • What is prediction variance? Digby
    Digby Millikan Aug 24, 2005
  • What does the 'ai' stand for in 'ai-geostats'
    Digby Millikan Jun 7, 2005
  • Kevin, You may also be interested in this website, if you select the applet and a skewed distribution, you can see examples of sample distributions. http://www.intuitor.com/statistics/CentralLim.html Digby
    Digby Millikan May 17, 2005
  • David, A few questions, How would you determine the number of samples? When you say sampling problem, do you mean problems in the laboratory? btw Michel David's example of the use of sichel t-estimator is the use of five samples from Harmony Mine. He also goes onto discuss pro's and con's of having 5 samples i.e. arithmetic mean of 5 samples 1195 in-dwt (47.2 gram.metres) sichel...
    Digby Millikan May 13, 2005
  • Treatment of gold outliers from belt samples It seems your ore on the belt may have mixed up a bit since being part of the orebody, and also only represents a small part of the orebody. According to the central limit thereom "if a series of samples, of size n, are taken from a population (not necessarily normal) with mean u, and standard deviation s, then the sample means will form...
    Digby Millikan May 13, 2005
  • Richard, If you wish to use the chip samples to estimate the mean the formulea for the estimate of the mean of a lognormal population is; T* = exp(u* + 0.5 s*^2) pp73 Practical Geostatistics 2000 I. Clark i.e. you need to have the variance of the samples to estimate the mean. The problem is that the variance of the chip samples is different from the variance of the blocks they...
    Digby Millikan May 13, 2005