[R] lm, coefficient 'not defined because of singularities'? What does this mean?

[Martin Waller]

Ah yes - you're right, and its also a tiny number (10^-18)

Thanks...

Martin

Patrick Burns wrote:
> I think it is saying that there is only one (unique)
> number in 'x1'.  If that is right, then you could do:
>
> lm(y1 ~ x1 - 1)
>
> Patrick Burns
> patrick at burns-stat.com
> +44 (0)20 8525 0696
> http://www.burns-stat.com
> (home of S Poetry and "A Guide for the Unwilling S User")
>
> Martin Waller wrote:
>
>> Hello,
>>
>> I'm doing an lm(y1~x1), no NAs in them, both of length 283.
>>
>> I get out however and 'NA' for the estimate of x1 and summary gives:
>>
>> Residuals:
>>     Min    1Q    Median    3Q    Max
>> -0.1998309 -0.0447269 -0.0006252  0.0390933  0.3141687
>>
>> Coefficients: (1 not defined because of singularities)
>>     Estimate Std. Error t value Pr(>|t|)
>> (Intercept) -0.021291   0.003994   -5.331 2.01e-07 ***
>> x1                  NA        NA       NA       NA
>> ---
>> Signif. codes: 0 .***. 0.001 .**. 0.01 .*. 0.05 '.' 0.1 ' ' 1
>>
>> Residual standard error: 0.06719 on 282 degrees of freedom
>>
>>
>> I don't understand why x1 can't be defined because of singularities - 
>> is it trying to tell me something about the data and what can I do 
>> about it?
>>
>> Thanks for any help,
>>
>> Martin
>>
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>>
>>  
>>
>
>