A likelihood ratio or Wald X² test formally tests the hypothesis of whether the model
fits the data better than no model.
It is common to test whether the model fits the data better than the null model with no
A X2 test formally tests whether the reduction is statistically significant. The
null hypothesis states that all the parameters for the covariates are zero against the
alternative that at least one parameter is not equal to zero. When the p-value is small, you can
reject the null hypothesis and conclude that at least one parameter is not zero.