[R-sig-ME] glmmTMB's variance-covariance matrix is of the vector of observed intercept per subject minus the quantity of the fixed intercept plus the random-intercept term?
Sun, John
j@un20 @end|ng |rom @|b@ny@edu
Mon Oct 10 23:50:21 CEST 2022
Dear All,
I am writing to ask which random-vector glmmTMB estimates the variance-covariance matrix. Is the random-vector that glmmTMB the G-matrix Charles Roy Henderson describes in https://en.wikipedia.org/wiki/Mixed_model?
Suppose we have a model with random-intercepts and fixed-effects. Is the random-vector that glmmTMB estimates the variance-covariance of equal to the actual random-intercept of the individual minus the quantity of the random-effect plus the fixed-intercept effect?
The random-intercept for some individual equals the intercept's random-effect plus the fixed-effect of the intercept plus some random-error scalar drawn from a normal distribution.
I refer to the equation in the second level of the two-level model.
The level one equation equals alpha_i+beta*Xij + epsilon_i.
The level two: alpha_i=delta+gamma_i + h_i.
"I" is subject, j is timepoint. Delta is fixed-intercept term, gamma_i is individual's deviation from the fixed-intercept. h_i is some deviation of the individual from the fixed-effect drawn from some normal distribution.
Best regards,
John
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