[R] missing values in step procedure

[Bernardo Rangel Tura]

At 11:11 7/10/2005, you wrote:

>Hi,
>I have the problem that for the step procedure stops due to missing
>values. There are no options in Step or stepAIC to handle missing
>values. Is there any way to run stepwise modelselection in R in an
>automated way in this case?
>
>Here is the last step before it stops. Hope someone knows. Best regards,
>Andreas
>
>Step:  AIC= 1999.16
>  EF ~ SF120_KS + SF120_PS + HADA0 + SOZU0 + LVEDD + logPROBNP +
>     ALTER + SD0_01 + ASE_UK + DS140POS + RSQSICH0 + SD0_01:ASE_UK +
>     SD0_01:DS140POS + SD0_01:RSQSICH0 + ASE_UK:DS140POS +
>ASE_UK:RSQSICH0 +
>     DS140POS:RSQSICH0 + SD0_01:ASE_UK:RSQSICH0 +
>SD0_01:DS140POS:RSQSICH0 +
>     ASE_UK:DS140POS:RSQSICH0
>
>                            Df Sum of Sq     RSS     AIC
>- SOZU0                     1       3.0 25356.0  1997.2
>- HADA0                     1       7.6 25360.6  1997.3
>- ALTER                     1      13.0 25365.9  1997.4
>- SF120_PS                  1      14.7 25367.6  1997.5
>- ASE_UK:DS140POS:RSQSICH0  1      20.1 25373.1  1997.6
>- SD0_01:DS140POS:RSQSICH0  1      44.8 25397.7  1998.0
>- SD0_01:ASE_UK:RSQSICH0    1      54.4 25407.4  1998.2
><none>                                  25352.9  1999.2
>- LVEDD                     1     382.2 25735.1  2004.6
>- SF120_KS                  1     476.4 25829.3  2006.4
>- logPROBNP                 1     891.9 26244.9  2014.4
>Error in step(mod2, direction = "back") :
>         number of rows in use has changed: remove missing values?

Andreas

Try

data<-na.omit(original database) before you run step() or stepAIC()




Bernardo Rangel Tura, MD, MSc
National Institute of Cardiology Laranjeiras
Rio de Janeiro Brazil  


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