search for: extractvars

...y ~ d+ 3*r+t I want to add a variable p, so > update(y~d+0*r+t, .~.+p) produces y ~ d + t + p - 1 If the coefficient is not 0, but rather, something else - say, 3, I get the following: > update(y~d+3*r+t, .~.+p) Error in terms.formula(tmp, simplify = TRUE) : invalid model formula in ExtractVars > Is there a way to do this, or a different call I should be trying? -Jarrett

...e of my variables. > When using this variable as continuous the anova works without problem, > but if using the same variable as factor (in fact, this is what it is), the > program returns this answer: > > Error in terms.formula(formula, data = data) : > invalid model formula in ExtractVars > > > any ideas on what might be the problem? > > Cheers! > > > > -- > BAS > > > [[alternative HTML version deleted]]

...4alternative hypothesis: true difference in means is not equal to 0 95 percent confidence interval: -3.3654832 0.2054832 sample estimates:mean in group 1 mean in group 2 0.75 2.33 > t.test((1:6)~rep(1:2,each=3))Error in terms.formula(formula[-3]) : invalid model formula in ExtractVars> t.test(2^(1:6)~rep(1:2,each=3))Error in terms.formula(formula[-3]) : invalid power in formula> t.test(2^extra ~ group, data = sleep)Error in terms.formula(formula[-3]) : invalid power in formulaUnix session: (R 2.3.1)============================> R.version _...

...+ + CAT10+s(NUM06,5)+CAT11+NUM07+CAT12+CAT13, + family = binomial(link = logit), data = train.data,na.action = na.exclude, + control = list(epsilon = 0.001,bf.epsilon = 0.001, maxit = 50, + bf.maxit = 10, trace = F)) Error in terms.formula(reformulate(term[i])) : invalid model formula in ExtractVars And after deleting df's model.gam <- gam(formula = RES ~ CAT01+s(NUM01)+CAT02+CAT03+s(NUM02)+CAT04+ + CAT05+s(NUM03)+CAT06+CAT07+s(NUM04)+CAT08+s(NUM05)+CAT09+ + CAT10+s(NUM06)+CAT11+NUM07+CAT12+CAT13, + family = binomial(link = logit), data = train.data) Error in smooth.construct.tp.smo...

...205694_at" + "201909_at" + "208894_at" + "216512_s_at" + "205337_at" + "201850_at" + "210982_s_at") >lm1=lm(fm1,data1new) And I receive the following error: Error in terms.formula(formula, data = data) : invalid model formula in ExtractVars *I have also tried:* >cols=rownames(data3) %%%%Where data3 is the same data frame with data above, but without the "norm" row binded yet thus: > cols [1] "206427_s_at" "205338_s_at" "209848_s_at" "205694_at" "201909_at" [6] &q...

Unfortunately that's not really an R question. I recommend that you read up on the statistical methods underneath. One that I'd wholeheartedly recommend is Prof. Harrell's `Regression Modeling Strategies'. [BTW, there are now two implementations of gam() in R: one in `mgcv', which is fairly different from that in `gam'. I'm guessing you're referring to the one