Table 3

Power analysis

F tests – ANOVA: Fixed effects, omnibus, one-way

Analysis:

A priori: Compute required sample size

Input:

Effect size f

0.25

α error probability

0.05

Power (1-β error probability)

0.80

Number of groups

3

Output:

Non-centrality parameter λ

9.938

Critical F

3.054

Numerator df

2

Denominator df

156

Total sample size

159

Actual power

0.805


Blankers et al. BMC Public Health 2009 9:16   doi:10.1186/1471-2458-9-16

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