search for: metabr

Displaying 2 results from an estimated 2 matches for "metabr".

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2009 Feb 26
4
Singularity in a regression?
R friends, In a matrix of 1s and 0s, I'm getting a singularity error. Any helpful ideas? lm(formula = activity ~ metaF + metaCl + metaBr + metaI + metaMe + paraF + paraCl + paraBr + paraI + paraMe) Residuals: Min 1Q Median 3Q Max -4.573e-01 -7.884e-02 3.469e-17 6.616e-02 2.427e-01 Coefficients: (1 not defined because of singularities) Estimate Std. Error t value Pr(>|t|) (...
2007 Aug 30
1
categorical variable coefficients in QSAR
Dear list: I am interested in the following sort of problem, as is found frequently in the field of QSAR. I have biological activity as a function of chemical structure, with structure defined in a categorical manner in that the SUBSTITUENT is the levels of the POSITION factor. For example, data from Kubinyi (http://www.kubinyi.de/dd-12.pdf) for this type of analysis is presented as follows: