Contents
Can a generalized linear mixed model be used for power analysis?
With the aim of encouraging the use of power analysis, we present simulation from generalized linear mixed models (GLMMs) as a flexible and accessible approach to power analysis that can account for random effects, overdispersion and diverse response distributions.
How is the generalized linear mixed model used in EE?
Neither random effects nor count responses are handled in relatively sophisticated power analysis software such as g*power (Faul et al. 2007 ). The generalized linear mixed model (GLMM) is an analysis framework widely used in EE that can accommodate these complexities.
How to calculate power of a mixed effect model?
To calculate power we to regress the simulated data in the same way we did the pilot data, and check for a significant β. Since optimization is done using numeric methods there is always the chance that the optimization will not work. So, we make sure the regression on the fake data catches and recovers from all errors.
Why is my linear mixed model not stable?
In part, this may also reflect limitations of optimizers in the available computer programs. As a consequence, the program may not converge to a stable solution; the model is overparameterized or degenerate relative to the information in the data.
How to plot A binomial GLMM with a proportional response variable?
How to plot (in R) a binomial GLMM with a proportional response variable [cbind (Successes, Failures) variable], and a continuous fixed factor? How to plot (in R) a binomial GLMM with a proportional response variable [analyzed using cbind (Successes, Failures)], and a continuous fixed factor?
Which is the first step in simulation based power analysis?
The first step of simulation-based power analysis is to simulate a large number of data sets. When simulating responses from a GLMM, we must assume values for the intercept and the regression coefficients (the fixed effects) and the variances and covariances of the random effects.
How does a power analysis in SIMR work?
A power analysis in simr starts with a model fitted in lme 4. This will typically be based on an analysis of data from a pilot study, but more advanced users can create artificial pilot data from scratch (see Appendix S2). This design allows for a gentle learning curve for any users already familiar with lme 4.