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. Author manuscript; available in PMC: 2014 Jul 16.
Published in final edited form as: Ann Biom Biostat. 2013 Jul 5;1(1):1002.

Table 2.

The correlation (ρmax) that maximizes the variance of the statistic or the required sample size and the variance ratio (VR) as a function of the number of repeated measures (k) and the ratio (R) of the neighboring standard deviations in the heterogeneous model. (R2 is the ratio of the neighboring variances.

K R R2 ρ max VR
2 0.8 0.64 0.2469 0.5671
0.9 0.81 0.2493 0.5635
1.0 1.0 0.2500 0.5625
1.1 1.21 0.2494 0.5633
1.2 1.44 0.2479 0.5656
1.3 1.69 0.2457 0.5689
1.5 2.25 0.2400 0.5776
2.0 4.00 0.2222 0.6049
3 0.8 0.64 0.3279 0.4518
0.9 0.81 0.3321 0.4461
1.0 1.0 0.3333 0.4444
1.1 1.21 0.3323 0.4458
1.2 1.44 0.3297 0.4493
1.3 1.69 0.3258 0.4545
1.5 2.25 0.3158 0.4681
2.0 4.00 0.2857 0.5102
4 0.8 0.64 0.3674 0.4002
0.9 0.81 0.3733 0.3928
1.0 1.0 0.3750 0.3906
1.1 1.21 0.3736 0.3924
1.2 1.44 0.3699 0.3971
1.3 1.69 0.3645 0.4038
1.5 2.25 0.3508 0.4215
2.0 4.00 0.3111 0.4746