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Table 1 a priori sample size calculations to detect small, medium, and large effects for endothelial function research

From: Statistical Inferences Using Effect Sizes in Human Endothelial Function Research

Effect size

Paired samples t test (n = number of pairs)

Independent samples t test (n = per group)

Small (d = 0.28)

102

202

Medium (d = 0.69)

19

34

Large (d = 1.21)

8

12

  1. Tests were calculated using 80% power, and assuming a two-tailed test and α = 0.05. Researchers may use alternative levels of statistical power (Fig. 6), however, 80% typically represents the minimally acceptable level of statistical power (Quintana [12])