Hi all, I am trying to fit full quadratic model i.e liear + square + interaction terms to my data (216 data points), so in my case coefficients are 28 (6 parameters). When i look into summary lm() of model all cross terms coefficients are NA. What does this mean? Is the regression is not able to solve for these coefficients due to some reason. Or does this mean that i should not consider these terms. Regards,
vinod gullu wrote:> Hi all, > I am trying to fit full quadratic model i.e liear + > square + interaction terms to my data (216 data > points), so in my case coefficients are 28 (6 > parameters). When i look into summary lm() of model > all cross terms coefficients are NA. What does this > mean? Is the regression is not able to solve for these > coefficients due to some reason. Or does this mean > that i should not consider these terms.Are there any factors with more than 2 levels? We need some more details... Uwe Ligges> Regards, > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.