Hi Luis, Well, when I copied your code I discovered that On Wed, Feb 2, 2011 at 9:42 AM, Luis Ridao <luri...@gmail.com> wrote: > R-help, > > I'm using the "update" command for a multiple regression model and it is > just not working: > >> update(model1, . ~ . – temp:wind:rad,data=ozone.pollution) ^ this is not a minus sign! Are you using a word processer to write your code?
update(ozone ~ temp * wind * rad + I(rad^2) + I(temp^2) + I(wind^2), . ~ . -temp:wind:rad) works for me. Best, Ista > Error: unexpected input in "model2<-update(model1, . ~ . –" > >> summary(model1) > > Call: > lm(formula = ozone ~ temp * wind * rad + I(rad^2) + I(temp^2) + > I(wind^2), data = ozone.pollution) > > Residuals: > Min 1Q Median 3Q Max > -38.894 -11.205 -2.736 8.809 70.551 > > Coefficients: > Estimate Std. Error t value Pr(>|t|) > (Intercept) 5.683e+02 2.073e+02 2.741 0.00725 ** > temp -1.076e+01 4.303e+00 -2.501 0.01401 * > wind -3.237e+01 1.173e+01 -2.760 0.00687 ** > rad -3.117e-01 5.585e-01 -0.558 0.57799 > I(rad^2) -3.619e-04 2.573e-04 -1.407 0.16265 > I(temp^2) 5.833e-02 2.396e-02 2.435 0.01668 * > I(wind^2) 6.106e-01 1.469e-01 4.157 6.81e-05 *** > temp:wind 2.377e-01 1.367e-01 1.739 0.08519 . > temp:rad 8.403e-03 7.512e-03 1.119 0.26602 > wind:rad 2.054e-02 4.892e-02 0.420 0.67552 > temp:wind:rad -4.324e-04 6.595e-04 -0.656 0.51358 > --- > Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 > > Residual standard error: 17.82 on 100 degrees of freedom > Multiple R-squared: 0.7394, Adjusted R-squared: 0.7133 > F-statistic: 28.37 on 10 and 100 DF, p-value: < 2.2e-16 > >> > > Can anyone help with this? > > Thanks in advance > > [[alternative HTML version deleted]] > > > ______________________________________________ > R-help@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. > > -- Ista Zahn Graduate student University of Rochester Department of Clinical and Social Psychology http://yourpsyche.org ______________________________________________ R-help@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.