Digby, What do you mean "You also may wish to consider volume-variance relationships when comparing the chip sample means and the conveyor belt means, as the sample sizes are different"?
The volume-variance relationship does not affect the mean - it is concerned with the changes in variance at different support (volume) sizes. If you sample the belt using a pair of tweezers and large shovels then the means of each of these group of samples should be the same (given sampling is carried out correctly) - it will be the variance that changes (higher variance in the smaller (tweezer) samples, lower variance in the larger (shovel) samples). Cheers Richard Hague ----- Original Message ----- >Digby Millikan <[EMAIL PROTECTED]> >To: ai-geostats <[email protected]>, Kevin Lowe (Office Park)><[EMAIL PROTECTED]> >Subject: Re: [ai-geostats] Treatment of gold outliers from belt samples >Date: Fri, 13 May 2005 15:23:12 +0930 >Attachments: message-footer.txt,Size: 292 bytes. >Click here to clean up the attachments on mail2webServer >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 a distribution which tends to >the normal distribution as n increases whatever the population >distribution." I have a copy of Sichel's paper and a sample >of the mean estimate calculation, which I can send you. You also may wish >to consider volume-variance relationships when comparing the chip sample >means and the conveyor belt means, as the sample sizes are different. > >Regards Digby -------------------------------------------------------------------- mail2web - Check your email from the web at http://mail2web.com/ .
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