[R] model formula

[Eik Vettorazzi]

Hi Stephen,
have a look at ?update.formula

glm.turn.3<-update(glm.turn.2,.~.-termfac1:rate)

should do the trick.
hth.

Am 11.08.2011 17:27, schrieb Bond, Stephen:
> Hello useRs,
> 
> Pls help with removing a single interaction term from a formula:
> 
> summary(
>         glm.turn.2 <- glm(cbind(turn.cnt,tot.cnt-turn.cnt)~sn+poly(relAge,2,raw=T)+termfac+rate:termfac,data=fix,
>                   family="quasibinomial")
>         )
> 
> Gives
> 
> Coefficients:
>                            Estimate Std. Error t value Pr(>|t|)
> (Intercept)               -7.028467   0.106002 -66.305  < 2e-16 ***
> snFeb                      0.156963   0.023660   6.634 3.27e-11 ***
> snMar                      0.317540   0.022883  13.876  < 2e-16 ***
> snApr                      0.526084   0.022004  23.908  < 2e-16 ***
> snMay                      1.026710   0.020347  50.460  < 2e-16 ***
> snJun                      0.841044   0.021318  39.452  < 2e-16 ***
> snJul                      0.668790   0.022530  29.685  < 2e-16 ***
> snAug                      0.544267   0.022580  24.104  < 2e-16 ***
> snSep                      0.389667   0.023363  16.679  < 2e-16 ***
> snOct                      0.351294   0.023586  14.894  < 2e-16 ***
> snNov                      0.391464   0.024057  16.272  < 2e-16 ***
> snDec                     -0.373369   0.028755 -12.985  < 2e-16 ***
> poly(relAge, 2, raw = T)1  2.952887   0.067455  43.776  < 2e-16 ***
> poly(relAge, 2, raw = T)2 -1.783907   0.064074 -27.841  < 2e-16 ***
> termfac2                  -0.681719   0.128571  -5.302 1.14e-07 ***
> termfac3                  -1.032416   0.146396  -7.052 1.77e-12 ***
> termfac4                  -1.267011   0.108940 -11.630  < 2e-16 ***
> termfac5                  -1.009922   0.213129  -4.739 2.15e-06 ***
> termfac6                   3.300301   0.203465  16.221  < 2e-16 ***
> termfac1:rate              0.012274   0.019895   0.617    0.537
> termfac2:rate              0.121724   0.013472   9.036  < 2e-16 ***
> termfac3:rate              0.175232   0.018987   9.229  < 2e-16 ***
> termfac4:rate              0.197726   0.005787  34.164  < 2e-16 ***
> termfac5:rate              0.145622   0.027295   5.335 9.56e-08 ***
> termfac6:rate             -0.362379   0.025261 -14.345  < 2e-16 ***
> 
> and I would like to remove the termfac1:rate interaction. Is there a way to do that?
> Thank you
> 
> Stephen Bond
> 
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

-- 
Eik Vettorazzi

Department of Medical Biometry and Epidemiology
University Medical Center Hamburg-Eppendorf

Martinistr. 52
20246 Hamburg

T ++49/40/7410-58243
F ++49/40/7410-57790