My project involves stink bug sampling on soybeans and I'm using Taylor's Power law (
logvar ~ logmean) to use its parameters in the development of a sampling plan.
I'm using a mixed effect model to analyze the effect of fixed and random effects on intercept and slopes of logvar:
- fixed effects: log mean + state(8 states) + location (field interior vs. field edge) + lifestage (adult insect vs. nymph insect)
- random effects: field(46 fields) and location (18 locations)
My data is normally distributed and I'm using
lmer() to analyze it.
lmer(logvar ~ logmean + state + location + lifestage + (1|field) + (1|location), mydata)
In the R output I have 0 variances and Std. Error for either field and location random effects.
Does it means that adding these effects to my model does not explain any variance in the logvar?