Table 2.

Correlations of anomodont species diversity through time with different proxies for formation numbers, showing rank-order correlations for the raw data and for first differences (FD) and generalized differences (GD)

Spearman's ρP
Anomodont-bearing formations0.600.034*
Randomized species numbers (n=40)0.53–0.660.015*−0.062
 Mode0.600.029*
 Mean0.600.033*
FD anomodont-bearing formations0.580.041*
GD anomodont-bearing formations0.760.006**
All tetrapod-bearing formations−0.220.472
FD all tetrapod-bearing formations−0.130.646
GD all tetrapod-bearing formations−0.120.716
  • Probabilities (P) for each correlation measure are given, and these are marked as significant (P<0.5*) and highly significant (P<0.005**).