Dear r-eco-list users, This is not an R-question, but a statistical one, but maybe somebody can help. I had read that to set random points over an area and picking the nearest plant is not random sample, but I could not recover this article. Is that correct? Could you provide some basic reference? Thanks a lot Paulo -- Paulo In?cio de Knegt L?pez de Prado Depto. de Ecologia - Instituto de Bioci?ncias - USP Rua do Mat?o, travessa 14, n? 321 Cid. Universit?ria, S?o Paulo - SP CEP 05508-900 11-30917599 (sala) 11-30917600 (Secretaria)
Neighbor sampling is random?
4 messages · Paulo Inácio de Kn?==?ISO-8859-1?Q?egt López de Prado, Kingsford Jones, Paulo Prado
This may help a bit with intuition. Think about randomly picking a spot in the box below and then choosing the nearest neighbor. What's the inclusion probability for 1? What about 6? Clearly not a simple random sample... ----------- |123 | |456 | | | | | ----------- hth, Kingsford Jones 2009/7/4 Paulo In?cio de Knegt L?pez de Prado <prado at ib.usp.br>:
Dear r-eco-list users, This is not an R-question, but a statistical one, but maybe somebody can help. I had read that to set random points over an area and picking the nearest plant is not random sample, but I could not recover this article. Is that correct? Could you provide some basic reference? Thanks a lot Paulo -- Paulo In?cio de Knegt L?pez de Prado Depto. de Ecologia - Instituto de Bioci?ncias - USP Rua do Mat?o, travessa 14, n? 321 Cid. Universit?ria, S?o Paulo - SP CEP 05508-900 11-30917599 (sala) 11-30917600 (Secretaria)
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Thank very much to all. Kingsford's comment remind me that a general way to demonstrate this is trough a Dirichlet tessellation. Best Paulo
Paulo Prado wrote:
Dear r-eco-list users, This is not an R-question, but a statistical one, but maybe somebody can help. I had read that to set random points over an area and picking the nearest plant is not random sample, but I could not recover this article. Is that correct? Could you provide some basic reference? Thanks a lot Paulo -- Paulo In?cio de Knegt L?pez de Prado Depto. de Ecologia - Instituto de Bioci?ncias - USP Rua do Mat?o, travessa 14, n? 321 Cid. Universit?ria, S?o Paulo - SP CEP 05508-900 11-30917599 (sala) 11-30917600 (Secretaria)
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View this message in context: http://n2.nabble.com/Neighbor-sampling-is-random--tp3205663p3208482.html Sent from the r-sig-ecology mailing list archive at Nabble.com.
On Sun, Jul 5, 2009 at 9:42 AM, Paulo Prado<prado at ib.usp.br> wrote:
Thank very much to all. Kingsford's comment remind me that a general way to demonstrate this is trough a Dirichlet tessellation.
Indeed -- where calculation of statistics would require weighting by the inverse of the tile areas (inclusion probabilities)....
Best Paulo Paulo Prado wrote:
Dear r-eco-list users, This is not an R-question, but a statistical one, but maybe somebody can help. I had read that to set random points over an area and picking the nearest plant is not random sample, but I could not recover this article. Is that correct? Could you provide some basic reference? Thanks a lot Paulo -- Paulo In?cio de Knegt L?pez de Prado Depto. de Ecologia - Instituto de Bioci?ncias - USP Rua do Mat?o, travessa 14, n? 321 Cid. Universit?ria, S?o Paulo - SP CEP 05508-900 11-30917599 (sala) 11-30917600 (Secretaria)
_______________________________________________ R-sig-ecology mailing list R-sig-ecology at r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology
-- View this message in context: http://n2.nabble.com/Neighbor-sampling-is-random--tp3205663p3208482.html Sent from the r-sig-ecology mailing list archive at Nabble.com.
_______________________________________________ R-sig-ecology mailing list R-sig-ecology at r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-ecology