Compute Probabilities for Target Recognition

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Description

The hypergeometric distribution is used to infer if the number of anomalous sites along a traverse reliably reflect the presence of the dispersion pattern from a known mineral occurrence. The function displays the probability of the observed outcome could be due to chance alone.

Usage

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gx.hypergeom(tt, aa, kk, xx)

Arguments

tt

total number of sites along a traverse.

aa

number of sites that a priori should be anomalous.

kk

total number of > threshold sites.

xx

number of the aa that are > threshold.

Details

See Stanley (2003) for details, the examples below reproduce the results in Table 1 and Table 2.

Note

Effectively, the hypothesis being tested is that the pattern of above threshold (see fences), sites coincides the the expected dispersion pattern from a known mineral occurrence. This requires that the geochemist uses knowledge of the dispersion processes active along the traverse, both chemical and mechanical, to predict an expected dispersion pattern.

Author(s)

Robert G. Garrett

References

Stanley, C.R., 2003. Statistical evaluation of anomaly recognition performance. Geochemistry: Exploration, Environment, Analaysis, 3(1):3-12.

See Also

gx.runs

Examples

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## From Stanley (2003) Tables 1 and 2

gx.hypergeom(31, 10, 5, 3)
gx.hypergeom(31, 10, 3, 2)
gx.hypergeom(31, 10, 4, 3)

gx.hypergeom(31, 10, 4, 4)
gx.hypergeom(31, 10, 6, 5)
gx.hypergeom(31, 10, 3, 3)

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