how to use nlme fit why is it important for a model to be fixed nlme error putting random strain what is error in nlme what is an invalid formula nlme how do i find an invalid formula in r is the nlme model invalid what is the difference between nlme and lme is nlme invalid what is the correct formula for a nlme fit how to use nlme to fit a mixed model r nlme error in r why is hap in r an invalid formula what is the nlme error nlme error definition can you omit variables in the fit r formula why is the f nlme formula error what is nlme used for in r error in excel for fit variable what is the error in nlme