The LR.inter.cat.surv function performs a
likelihood ratio test (LRT) for an interaction term
between a categorical variable and a SNP (coded 0,1,2) in
a cox model. The function returns the p-value of the
likelihood ratio test.
LR.inter.cat.surv(x, formula, data, Z1)name or numeric vector corresponding to the SNP tested.
an object of class "formula" : a symbolic description of the model to be fitted without the interaction term.
a data frame containing the variables in the model.
name of the variable which is tested in interaction with x (x:Z1).
p-value of the likelihood ratio test for the interaction term.