I want to compare the poisson and the zero-inflated poisson distribution on describing the data. So, after using the GLM and the ZEROINFL function, I used the Voung function to compare them. Here is my code: library(pscl) glm1 <- glm(nmer9_1[, 1] ~ 1, family = poisson) zip <- zeroinfl(nmer9_1[, 1] ~ 1) vuong(glm1, zip) However, R returns the following error message: "Error: cannot allocate vector of size 3.3 Gb." Would you please tell me what was happening there? Please note that I am not trying to do a regression, but only want to compare which of the distributions explain the data better. Thank you. -- View this message in context: http://r.789695.n4.nabble.com/Error-Message-Comes-from-the-Vuong-Function-tp4385497p4385497.html Sent from the R help mailing list archive at Nabble.com.