Individuals                                  Number of events (n)
 N Test 2 10 50
50 Permutation 0.046 (0.0066) 0.047 (0.0067) 0.052 (0.0070)
  Mixture 0.005 (0.0022) 0.009 (0.0030) 0.016 (0.0040)
100 Permutation 0.045 (0.0066) 0.040 (0.0062) 0.052 (0.0070)
  Mixture 0.011 (0.0033) 0.019 (0.0043) 0.027 (0.0051)
200 Permutation 0.048 (0.0068) 0.052 (0.0070) 0.050 (0.0069)
  Mixture 0.015 (0.0038) 0.026 (0.0050) 0.031 (0.0055)
Table 1: Empirical level of significance of the score test for a frailty model (standard error in parenthesis).