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Table 1 Bias (standard deviation units) in respect of ANCOVA versus ANOVA and ANCOVA versus CSA

From: Bias, precision and statistical power of analysis of covariance in the analysis of randomized trials with baseline imbalance: a simulation study

Difference Z′ T –Z′ C Treatment effect
  0.2 0.5 0.8
  ZYcorrelation ZYcorrelation ZYcorrelation
   0 0.1 0.3 0.5 0.7 0.9 0 0.1 0.3 0.5 0.7 0.9 0 0.1 0.3 0.5 0.7 0.9
ANCOVA – ANOVA −1.96 0.00 0.01 0.04 0.07 0.10 0.13 0.00 0.03 0.10 0.17 0.24 0.31 0.00 0.05 0.16 0.27 0.38 0.49
−1.64 0.00 0.01 0.04 0.06 0.08 0.11 0.00 0.03 0.09 0.14 0.20 0.26 0.00 0.04 0.14 0.23 0.31 0.41
−1.28 0.00 0.01 0.03 0.05 0.06 0.08 0.00 0.02 0.07 0.11 0.16 0.20 0.00 0.03 0.10 0.17 0.25 0.32
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.00 0.00
1.28 0.00 −0.01 −0.03 −0.04 −0.06 −0.08 0.00 −0.03 −0.07 −0.11 −0.16 −0.21 0.00 −0.04 −0.11 −0.18 −0.25 −0.32
1.64 0.00 −0.01 −0.03 −0.06 −0.08 −0.11 0.00 −0.03 −0.09 −0.15 −0.21 −0.26 0.00 −0.05 −0.14 −0.23 −0.32 −0.41
1.96 0.00 −0.01 −0.04 −0.07 −0.10 −0.13 0.00 −0.04 −0.11 −0.18 −0.24 −0.31 0.00 −0.06 −0.17 −0.28 −0.38 −0.49
ANCOVA – CSA −1.96 −0.14 −0.13 −0.10 −0.07 −0.04 −0.01 −0.35 −0.31 −0.24 −0.17 −0.10 −0.03 −0.55 −0.49 −0.38 −0.27 −0.16 −0.05
−1.64 −0.12 −0.11 −0.08 −0.06 −0.04 −0.01 −0.29 −0.26 −0.20 −0.15 −0.09 −0.03 −0.46 −0.41 −0.31 −0.22 −0.14 −0.05
−1.28 −0.09 −0.08 −0.06 −0.05 −0.03 −0.01 −0.23 −0.20 −0.16 −0.12 −0.07 −0.03 −0.36 −0.32 −0.25 −0.17 −0.10 −0.03
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
1.28 0.09 0.08 0.06 0.05 0.03 0.01 0.23 0.20 0.16 0.11 0.07 0.02 0.35 0.32 0.25 0.18 0.11 0.04
1.64 0.12 0.10 0.08 0.06 0.04 0.01 0.29 0.26 0.20 0.15 0.09 0.03 0.45 0.41 0.32 0.23 0.14 0.05
  1.96 0.14 0.13 0.10 0.07 0.04 0.02 0.35 0.31 0.24 0.17 0.10 0.04 0.54 0.49 0.38 0.27 0.16 0.05