Table 3  Kendall's tau (rank correlation) comparing the most significant exact p-values (the reference) to the Karlin's approximations. The column "all" gives the result for all sequences while the Ri give the results for a certain range of sequence lengths: smaller than 100 for R1, between 100 and 200 for R2, between 200 and 500 for R3, between 500 and 1 000 for R4, between 1 000 and 2 000 for R5 and greater than 2 000 for R6.
number of p-values  all  R1  R2  R3  R4  R5  R6
10  0.30  0.64  0.24  -0.20  0.58  0.64  0.97
50  0.14  0.73  0.50  0.46  0.56  0.78  0.97
100  0.37  0.70  0.67  0.62  0.61  0.80  0.98