what model is used to model mixed effect what is nlme when to use the nlme model what model allows for random variable effects what model to use for random random effect regression? how to model nonlinear mixed effects in r how do you add fixed and random effect in sslogis how to model mixed effects in r how to do nls regression does nls work what is the starting value for an sslogis regression? nlme what parameters do nls have what is nlme nlme vs r what is nlme what is the starting value of p0 in nlme how to make r work for mixed effects what is the normal starting value for k when to use r regression r what model to use for sigmoid growth