[R] NA in lm()

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

Re: [R] NA in lm()

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