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Table 3 Estimated sample size needed per group in various scenarios

From: Sample size and power determination when limited preliminary information is available

DOSI Measure Power Significance level Estimated correlation coefficienta
0.50 0.80 0.90
Common STDb (σ) 2 × Common Variance Common STDb (σ) 2 × Common Variance Common STDb (σ) 2 × Common Variance
Water    σ = 2.121 σ = 2.999 σ = 1.420 σ = 2.008 σ = 1.088 σ = 1.539
80 0.01 69 136 32 62 20 38
  0.05 47 92 22 42 13 25
90 0.01 88 173 41 79 25 47
  0.05 62 122 29 56 17 33
Deoxyhemoglobin (ctHHb)    σ = 0.287 σ = 0.406 σ = 0.198 σ = 0.279 σ = 0.158 σ = 0.224
80 0.01 72 142 35 68 23 45
  0.05 48 95 24 46 16 30
90 0.01 90 180 45 86 29 56
  0.05 64 127 31 61 21 40
Lipid    σ = 2.633 σ = 3.724 σ = 1.816 σ = 2.568 σ = 1.443 σ = 2.041
80 0.01 96 191 47 92 31 59
  0.05 65 128 32 62 21 40
90 0.01 122 242 59 117 38 75
  0.05 86 171 42 80 27 53
  1. aThe correlation coefficient was estimated between pre- and post-treatment in simulated MRI data and in simulated DOSI measure
  2. bThe standard deviation is denoted as STD