[R] (... not defined because of singularities) in lm()

[Petr Pikal]

Hi

On 4 Aug 2006 at 16:44, Jia Pu wrote:

To:             	r-help at stat.math.ethz.ch
From:           	Jia Pu <jpu at apple.com>
Date sent:      	Fri, 4 Aug 2006 16:44:44 -0700
Subject:        	[R] (... not defined because of singularities) in lm()

> I got the message, " Coefficients: (1 not defined because of  
> singularities)", in the returned result of lm(). What does it mean? 
> And where should I start investigating why it happens?

one of your variables (probably isInterNuclear:zeroSyllToEOP) is a 
linear combination of other explanatory variables or is constant.

HTH
Petr



> 
> thanks.
> 
> 
> /// Complete result of lm()
> Call:
> lm(formula = durationRatio ~ isHStar + isWordFinal + oneSyllToEOW +
>      isInterNuclear + isIntonNuclear + isInterLP + isIntonLF +
>      zeroSyllToNA + oneSyllToNA + zeroSyllToEOP + oneSyllToEOP +
>      isInterNuclear:zeroSyllToEOP)
> 
> Residuals:
>        Min        1Q    Median        3Q       Max
> -3.031538 -0.126943 -0.002909  0.121606  4.322135
> 
> Coefficients: (1 not defined because of singularities)
>                                Estimate Std. Error t value Pr(>|t|)
> (Intercept)                   1.044481   0.010694  97.669  < 2e-16 ***
> isHStar                      -0.055227   0.005748  -9.607  < 2e-16 ***
> isWordFinal                  -0.262071   0.009982 -26.254  < 2e-16 ***
> oneSyllToEOW                 -0.031313   0.009917  -3.158  0.00160 **
> isInterNuclear                0.063470   0.015699   4.043 5.32e-05 ***
> isIntonNuclear                0.054570   0.011711   4.660 3.21e-06 ***
> isInterLP                    -0.262302   0.011868 -22.102  < 2e-16 ***
> isIntonLF                    -0.160018   0.012537 -12.764  < 2e-16 ***
> zeroSyllToNA                 -0.160767   0.011105 -14.477  < 2e-16 ***
> oneSyllToNA                  -0.012633   0.010779  -1.172  0.24123
> zeroSyllToEOP                -0.212474   0.011987 -17.726  < 2e-16 ***
> oneSyllToEOP                 -0.123324   0.010998 -11.214  < 2e-16 ***
> isInterNuclear:zeroSyllToEOP        NA         NA      NA       NA ---
> Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
> 
> Residual standard error: 0.2662 on 9650 degrees of freedom
> Multiple R-Squared: 0.3957,	Adjusted R-squared: 0.395
> F-statistic: 574.5 on 11 and 9650 DF,  p-value: < 2.2e-16
> 
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Petr Pikal
petr.pikal at precheza.cz