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Table 2 Example: Comparison of sample size formulas

From: Sample size calculation in multi-centre clinical trials

Block length Formula Number of centres
   c=23 c=46 c=92
6 \(N^{k}_{\text {lower}}\) 503 503 503
  \(N^{k}_{\mathrm {MC,E}}\) 525 524 569
  \(N^{k}_{\mathrm {MC,U}}\) 528 552 594
  \(N^{k}_{\text {upper}}\) 541 575 634
8 \(N^{k}_{\text {lower}}\) 503 503 503
  \(N^{k}_{\mathrm {MC,E}}\) 525 587 606
  \(N^{k}_{\mathrm {MC,U}}\) 535 564 616
  \(N^{k}_{\text {upper}}\) 551 592 662
16 \(N^{k}_{\text {lower}}\) 503 503 503
  \(N^{k}_{\mathrm {MC,E}}\) 586 603 762
  \(N^{k}_{\mathrm {MC,U}}\) 561 610 692
  \(N^{k}_{\text {upper}}\) 587 654 762
  1. Derived for μ=1,σ=4,ρ=0.5, varying block lengths and varying numbers of centres