search for: studynr

...conduct a meta-analysis, i.e. I'd like to use a multi-level model to integrate the findings of a number of primary research studies. I set up a simple two level-model (only summary statistics are provided by each study) as follows: sapp.lme <- lme(D ~ 1, data = sapp.frame, random = ~ 1 | STUDYNR, weights=varFixed(~-1+STDERR_D),na.action = na.exclude) The intercept is random on both levels and the variable stderr_D (the sampling variance) is supposed to be random only on level one. Besides, I need to constrain the variance of stderr_d to equal 1. Could anybody help me correct the code I...