I would appreciate pointers on what I should read to understand this output:
summary(lm(TDS ~ Cond + Ca + Cl + Mg + Na + SO4)) Call: lm(formula = TDS ~ Cond + Ca + Cl + Mg + Na + SO4) Residuals: ALL 1 residuals are 0: no residual degrees of freedom! Coefficients: (6 not defined because of singularities) Estimate Std. Error t value Pr(>|t|) (Intercept) 125 NA NA NA Cond NA NA NA NA Ca NA NA NA NA Cl NA NA NA NA Mg NA NA NA NA Na NA NA NA NA SO4 NA NA NA NA Residual standard error: NaN on 0 degrees of freedom (63 observations deleted due to missingness) When I look at the summary for the data frame used for this model I do not see an excessive number of missing values or indications why there are no residual degrees of freedom. The same model applied to 8 other data frames did not produce similar results. Puzzled, Rich ______________________________________________ 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.