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Hi, I'm running R 2.11.1 on Windows 32-bit. I fitted a glm to a "large" data set with no problems (i.e., nothing is wrong with the created glm object). However, when I try to use the "effects" package to plot the effects I get the error message shown below. I get the same message if I try to plot a single effect. Any idea what could be wrong here? glm.eff <-

When using function heckit() from package ‘sampleSelection’, is there anyway to make t-tests for the coefficients using robust covariance matrix estimator? By “robust” I mean something like if a had an object ‘lm’ called “reg” and then used: > coeftest(reg, vcov = vcovHC(reg)). I’m asking this because in Stata we could use function heckman and then use vce option “robust”. We could do the