[R] Singularity in a regression?

[ONKELINX, Thierry]

It looks like your data has not enough information to estimate the
parameter for metaCl. Maybe because metaCL is identical to one of the
other variables or a constant.
 
HTH,

Thierry

------------------------------------------------------------------------
----
ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature
and Forest
Cel biometrie, methodologie en kwaliteitszorg / Section biometrics,
methodology and quality assurance
Gaverstraat 4
9500 Geraardsbergen
Belgium 
tel. + 32 54/436 185
Thierry.Onkelinx at inbo.be 
www.inbo.be 

To call in the statistician after the experiment is done may be no more
than asking him to perform a post-mortem examination: he may be able to
say what the experiment died of.
~ Sir Ronald Aylmer Fisher

The plural of anecdote is not data.
~ Roger Brinner

The combination of some data and an aching desire for an answer does not
ensure that a reasonable answer can be extracted from a given body of
data.
~ John Tukey

-----Oorspronkelijk bericht-----
Van: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
Namens Bob Gotwals
Verzonden: donderdag 26 februari 2009 13:59
Aan: r-help at r-project.org
Onderwerp: [R] 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|)
(Intercept)   7.9173     0.1129  70.135  < 2e-16 ***
metaF        -0.3973     0.2339  -1.698 0.115172
metaCl            NA         NA      NA       NA
metaBr        0.3454     0.1149   3.007 0.010929 *
metaI         0.4827     0.2339   2.063 0.061404 .
metaMe        0.3654     0.1149   3.181 0.007909 **
paraF         0.7675     0.1449   5.298 0.000189 ***
paraCl        0.3400     0.1449   2.347 0.036925 *
paraBr        1.0200     0.1449   7.040 1.36e-05 ***
paraI         1.3327     0.2339   5.697 9.96e-05 ***
paraMe        1.2191     0.1573   7.751 5.19e-06 ***
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Residual standard error: 0.2049 on 12 degrees of freedom
Multiple R-squared: 0.9257,	Adjusted R-squared: 0.8699
F-statistic: 16.61 on 9 and 12 DF,  p-value: 1.811e-05

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