likelihood ratio test

> logLik.test
function(fit0,fit)
{
  l0 = logLik(fit0)
  l1 = logLik(fit)
  lratio = abs(as.numeric(l0)-as.numeric(l1))
  df = abs( attr(l1,'df') - attr(l0,'df') )
  pval = 1-pchisq( 2*lratio, df)
  return(pval)
}