Numerical Comparisons

We compared the different methods for the two situations discussed in Section 2. For the all-pairwise comparisons, we let $ I=4$ ($ q=6$) and $ {\bf V}=$diag$ (n_i^{-1})$. The specific values for $ n_i$ are given in Table 1. The table further presents the estimates $ \hat{t}_{1-\alpha}$ for each method and the associated probability $ T_k(-\hat{{\bf t}}_{1-\alpha}, \hat{{\bf t}}_{1-\alpha}; {\bf R},
\nu)$ are given in italics below. Critical values and probabilities were calculated with three significant digits of accuracy using the methods of Genz and Bretz (2002). For the $ I=4$ cases $ t^{(2,3)}_l$ and $ t^{(2,3)}_u$ seem to be good low-cost improvements over $ t^{(2)}_l$ (Dawson-Sankoff) and $ t^{(2)}_u$ (Hunter-Worsley). Further on, $ t^{(2,3)}_l$ appears to always be better than $ t^{(3)}_l$. The TK should not be used if the sample sizes differ by a large amount. Similar results apply to the other approximate correlation methods.

Table 1: Numerical results for all-pairwise comparisons with one-way layout ($ I=4$).

$ t^{(1)}_l$ $ t^{(2)}_l$ $ t^{(3)}_l$ $ t^{(2,3)}_l$ $ t_{1-\alpha}$ $ t^{(2,3)}_u$ $ t^{(3)}_u$ $ t^{(2)}_u$ $ t^{(1)}_u$ Šidák TK GT2 $ \bar{\rho}$ $ F$-test $ n_1$ $ n_2$ $ n_3$ $ n_4$
2.028 2.672 2.683 2.686 2.693 2.725 2.695 2.751 2.792 2.784 2.693 2.775 2.699 2.932 10 10 10 10
0.803 0.948 0.949 0.950 0.950 0.954 0.951 0.956 0.960 0.959 0.950 0.959 0.951 0.972
2.011 2.641 2.652 2.655 2.660 2.679 2.660 2.705 2.752 2.744 2.661 2.738 2.664 2.897 10 12 14 16
0.802 0.948 0.950 0.950 0.950 0.953 0.950 0.955 0.960 0.959 0.950 0.959 0.951 0.972
2.000 2.619 2.628 2.634 2.638 2.654 2.638 2.677 2.729 2.721 2.643 2.716 2.644 2.876 10 14 18 22
0.802 0.948 0.949 0.950 0.950 0.952 0.951 0.955 0.960 0.959 0.951 0.959 0.951 0.973
1.993 2.602 2.612 2.618 2.622 2.636 2.622 2.658 2.713 2.705 2.630 2.702 2.630 2.863 10 16 22 28
0.803 0.948 0.949 0.950 0.950 0.951 0.951 0.954 0.960 0.959 0.951 0.959 0.951 0.973
1.989 2.589 2.601 2.607 2.610 2.622 2.611 2.643 2.702 2.694 2.621 2.691 2.620 2.853 10 18 26 34
0.804 0.947 0.949 0.950 0.950 0.951 0.951 0.954 0.960 0.960 0.951 0.959 0.951 0.973
1.985 2.578 2.590 2.597 2.600 2.611 2.601 2.631 2.694 2.686 2.615 2.684 2.613 2.846 10 20 30 40
0.805 0.947 0.949 0.950 0.950 0.951 0.951 0.954 0.961 0.960 0.952 0.960 0.952 0.974
1.971 2.519 2.538 2.552 2.554 2.560 2.555 2.578 2.663 2.655 2.589 2.654 2.584 2.818 10 40 70 100
0.811 0.945 0.948 0.950 0.950 0.951 0.950 0.953 0.962 0.962 0.954 0.962 0.954 0.976
1.967 2.490 2.515 2.532 2.535 2.536 2.540 2.557 2.654 2.647 2.582 2.646 2.575 2.810 10 60 110 160
0.814 0.944 0.948 0.950 0.950 0.951 0.951 0.953 0.964 0.963 0.956 0.963 0.955 0.976
1.965 2.472 2.501 2.521 2.524 2.529 2.526 2.545 2.650 2.643 2.579 2.642 2.571 2.806 10 80 150 220
0.817 0.943 0.947 0.949 0.950 0.951 0.951 0.953 0.964 0.964 0.957 0.964 0.956 0.977
1.964 2.458 2.490 2.514 2.517 2.521 2.519 2.537 2.647 2.640 2.577 2.640 2.568 2.804 10 100 190 280
0.819 0.942 0.946 0.949 0.950 0.950 0.951 0.953 0.965 0.964 0.957 0.964 0.956 0.977
1.976 2.546 2.560 2.570 2.571 2.581 2.573 2.596 2.675 2.667 2.599 2.666 2.597 2.828 80 40 20 10
0.808 0.947 0.948 0.950 0.950 0.952 0.950 0.953 0.962 0.961 0.953 0.961 0.953 0.975
1.966 2.488 2.511 2.527 2.528 2.534 2.530 2.546 2.652 2.644 2.580 2.644 2.576 2.808 270 90 30 10
0.816 0.945 0.948 0.950 0.950 0.951 0.950 0.952 0.964 0.963 0.956 0.963 0.956 0.977
1.963 2.454 2.484 2.505 2.506 2.511 2.509 2.521 2.644 2.637 2.574 2.637 2.569 2.801 640 160 40 10
0.822 0.943 0.947 0.950 0.950 0.951 0.950 0.952 0.965 0.965 0.958 0.965 0.958 0.978
1.961 2.431 2.466 2.491 2.494 2.497 2.495 2.506 2.642 2.634 2.572 2.634 2.566 2.799 1250 250 50 10
0.825 0.941 0.946 0.950 0.950 0.951 0.950 0.953 0.967 0.966 0.959 0.966 0.958 0.978
1.961 2.414 2.454 2.482 2.484 2.487 2.487 2.496 2.640 2.633 2.571 2.633 2.564 2.797 2160 360 60 10
0.828 0.940 0.947 0.950 0.950 0.951 0.950 0.952 0.968 0.967 0.961 0.967 0.959 0.979
1.961 2.400 2.445 2.474 2.477 2.480 2.480 2.488 2.640 2.632 2.570 2.632 2.563 2.797 3430 490 70 10
0.830 0.939 0.945 0.950 0.950 0.950 0.950 0.951 0.969 0.967 0.961 0.967 0.960 0.980
1.960 2.393 2.437 2.468 2.471 2.474 2.475 2.481 2.639 2.632 2.570 2.632 2.562 2.796 5120 640 80 10
0.832 0.940 0.945 0.950 0.950 0.950 0.951 0.952 0.968 0.968 0.962 0.968 0.961 0.980
1.960 2.387 2.423 2.459 2.463 2.466 2.466 2.472 2.639 2.632 2.569 2.631 2.561 2.796 10000 1000 100 10
0.834 0.939 0.945 0.950 0.950 0.950 0.950 0.951 0.970 0.969 0.963 0.968 0.962 0.980

For the many-to-one comparisons we looked at $ J=2$ and $ I=5$ (if $ I \leq 4$, then $ q=I-1 \leq 3$ and (2) holds for any $ {\bf V}$ if the $ \lambda_i$'s are defined appropriately). Table 2 specifies the values for $ n_{i.}=\sum_j n_{ij}$. In all cases we set $ n_{i2}=2$, $ n_{i1}=n_{i.}-n_{i2}, i=1,2$ and $ n_{i1}=2,$ $ n_{i2}=n_{i.}-n_{i1}, i=3,4,5$ and . This ensures that the proportionality rule of Section 2 is violated. Similar results as for the all pairwise comparisons hold here. The hybrid bounds are found again to be good approximations to $ t_{1-\alpha}$. The Hsu method is usually accurate to three significant digits and is a good competitor to $ t^{(2,3)}_l$ and $ t^{(2,3)}_u$. The Solow method is easily implemented and performs good for low $ I$, but its performance deteriorates rapidly with increasing $ I$.

Table 2: Numerical results for many-to-one comparisons with two-way layout ($ I=5$).

$ t^{(1)}_l$ $ t^{(2)}_l$ $ t^{(3)}_l$ $ t^{(2,3)}_l$ $ t_{1-\alpha}$ $ t^{(2,3)}_u$ $ t^{(3)}_u$ $ t^{(2)}_u$ $ t^{(1)}_u$ Šidák Hsu Solow $ \bar{\rho}$ $ n_{1.}$ $ n_{2.}$ $ n_{3.}$ $ n_{4.}$ $ n_{5.}$
1.680 2.176 2.209 2.211 2.215 2.224 2.219 2.254 2.321 2.313 2.214 2.212 2.217 10 10 10 10 10
0.860 0.946 0.949 0.950 0.950 0.951 0.950 0.954 0.960 0.960 0.950 0.950 0.950
1.669 2.094 2.152 2.158 2.161 2.170 2.170 2.202 2.295 2.287 2.161 2.159 2.169 10 12 14 16 18
0.870 0.942 0.949 0.950 0.950 0.951 0.951 0.954 0.963 0.962 0.950 0.950 0.951
1.663 2.034 2.117 2.125 2.128 2.137 2.141 2.170 2.282 2.275 2.129 2.126 2.141 10 14 18 22 26
0.875 0.939 0.949 0.950 0.950 0.951 0.951 0.954 0.964 0.964 0.950 0.950 0.951
1.660 1.985 2.094 2.102 2.105 2.113 2.119 2.147 2.274 2.267 2.106 2.104 2.123 10 16 22 28 34
0.880 0.935 0.948 0.950 0.950 0.951 0.951 0.954 0.966 0.965 0.950 0.950 0.952
1.657 1.969 2.074 2.084 2.088 2.096 2.104 2.129 2.269 2.261 2.088 2.087 2.109 10 18 26 34 42
0.883 0.936 0.948 0.950 0.950 0.951 0.952 0.954 0.967 0.966 0.950 0.950 0.952
1.656 1.958 2.059 2.070 2.074 2.082 2.090 2.115 2.265 2.257 2.075 2.074 2.099 10 20 30 40 50
0.885 0.936 0.948 0.949 0.950 0.951 0.951 0.954 0.967 0.967 0.950 0.950 0.953
1.649 1.903 1.984 2.006 2.010 2.016 2.023 2.045 2.251 2.244 2.010 2.012 2.054 10 40 70 100 130
0.897 0.937 0.947 0.950 0.950 0.951 0.951 0.954 0.971 0.971 0.950 0.950 0.955
1.648 1.880 1.957 1.982 1.985 1.990 1.997 2.017 2.248 2.240 1.985 1.987 2.040 10 60 110 160 210
0.901 0.938 0.947 0.951 0.950 0.951 0.952 0.953 0.973 0.972 0.950 0.950 0.956
1.647 1.867 1.939 1.969 1.972 1.977 1.982 2.000 2.246 2.239 1.972 1.973 2.032 10 80 150 220 290
0.904 0.938 0.946 0.950 0.950 0.951 0.951 0.953 0.973 0.973 0.950 0.950 0.956
1.646 1.859 1.929 1.959 1.963 1.967 1.973 1.989 2.245 2.238 1.962 1.963 2.028 10 100 190 280 370
0.905 0.938 0.946 0.950 0.950 0.950 0.951 0.953 0.974 0.973 0.950 0.950 0.957
1.650 2.164 2.176 2.180 2.179 2.182 2.180 2.194 2.253 2.245 2.180 2.178 2.200 160 80 40 20 10
0.850 0.948 0.950 0.950 0.950 0.950 0.950 0.952 0.958 0.957 0.950 0.950 0.952
1.646 2.143 2.157 2.161 2.162 2.164 2.162 2.173 2.244 2.237 2.161 2.158 2.196 810 270 90 30 10
0.853 0.947 0.950 0.950 0.951 0.950 0.950 0.951 0.959 0.958 0.950 0.950 0.954
1.645 2.129 2.146 2.150 2.150 2.152 2.152 2.161 2.242 2.235 2.151 2.148 2.194 2560 640 160 40 10
0.855 0.948 0.950 0.950 0.950 0.950 0.950 0.951 0.960 0.959 0.950 0.949 0.954
1.645 2.120 2.139 2.145 2.145 2.146 2.145 2.154 2.242 2.234 2.144 2.141 2.194 6250 1250 250 50 10
0.856 0.947 0.949 0.950 0.950 0.951 0.950 0.952 0.961 0.960 0.950 0.950 0.955
1.645 2.115 2.135 2.141 2.140 2.143 2.141 2.148 2.242 2.234 2.139 2.136 2.193 12960 2160 360 60 10
0.858 0.946 0.949 0.950 0.950 0.950 0.950 0.951 0.961 0.960 0.950 0.950 0.956
1.645 2.108 2.129 2.135 2.135 2.137 2.136 2.144 2.242 2.234 2.135 2.134 2.193 24010 3430 490 70 10
0.859 0.947 0.949 0.950 0.950 0.950 0.950 0.951 0.961 0.960 0.950 0.950 0.956
1.645 2.104 2.125 2.133 2.132 2.135 2.133 2.141 2.241 2.234 2.132 2.130 2.193 40960 5120 640 80 10
0.859 0.946 0.949 0.950 0.950 0.950 0.949 0.951 0.962 0.961 0.950 0.950 0.956
1.645 2.097 2.121 2.127 2.128 2.129 2.128 2.135 2.241 2.234 2.128 2.125 2.192 100000 10000 1000 100 10
0.861 0.946 0.949 0.950 0.950 0.950 0.950 0.951 0.962 0.961 0.950 0.949 0.958




2003-02-17