I have a data set with 35 observations and 4 variables. I have removed 4 observations as they were skewing the data analysis but I want to dummy them back in, (not entirely sure on the reason, but have been told I should try).
I have used this in order to do it, but I am not getting any statistical analysis with my dummy it's all NA. > dummy15=rep(0, times=n) > dummy15[15]=1 > which(psubset1==0) [1] 10 15 21 27 > dummytest = lm(price ~ pct.children + wealth + pct.walk + pct.emp + > dummy15, data = mydata, *subset = as.logical(subset)*) > summary(dummytest) Call: lm(formula = price ~ pct.children + wealth + pct.walk + pct.emp + dummy15, data = mydata, *subset = as.logical(subset)*) Residuals: Min 1Q Median 3Q Max -32708 -8861 383 8492 22609 Coefficients: (1 not defined because of singularities) Estimate Std. Error t value Pr(>|t|) (Intercept) 7.545e+04 1.073e+04 7.030 1.82e-07 *** pct.children 3.541e+03 4.069e+02 8.703 3.52e-09 *** wealth 1.450e-01 1.894e-02 7.654 4.01e-08 *** pct.walk -2.727e+03 6.007e+02 -4.539 0.000113 *** pct.emp 4.785e+03 1.556e+03 3.075 0.004903 ** dummy15 NA NA NA NA --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 Residual standard error: 13950 on 26 degrees of freedom Multiple R-squared: 0.9618, Adjusted R-squared: 0.9559 F-statistic: 163.6 on 4 and 26 DF, p-value: < 2.2e-16 If I take out the section highlighted in bold, my summary of the model includes all the other observations I have previously taken out, 10, 21 and 27. I hope this makes sense? if not I'd be happy to try and clarify anything. Thank you very much for any help -- View this message in context: http://r.789695.n4.nabble.com/Summary-model-with-observations-taken-out-and-dummied-back-in-not-working-tp4176123p4176123.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.