I am using the
assocstats function in the
vcd library. It gives something called the likelihood ratio and its associated p-value which is different from the chi-squared statistic and its p-value. What is this likelihood ratio and what is it's distribution?
> library(vcd) > data("Arthritis") > tab <- xtabs(~Improved + Treatment, data = Arthritis) > assocstats(tab) X^2 df P(> X^2) Likelihood Ratio 13.530 2 0.0011536 Pearson 13.055 2 0.0014626 Phi-Coefficient : NA Contingency Coeff.: 0.367 Cramer's V : 0.394 > chisq.test(tab) Pearson's Chi-squared test data: tab X-squared = 13.055, df = 2, p-value = 0.001463