samplesize.etasq: Sample size estimation in the analysis of variance

In rpsychi: Statistics for psychiatric research

Description

samplesize.etasq determines the sample size, when specified the number of group, effect size to be detected, desired statistical power, and significance level.

Usage

samplesize.etasq(k, delta, power=.80, sig.level=.05)

Arguments

k	a numeric contains the number of group
delta	a numeric contains the effect size (η^2) to be detected
power	a numeric contains the desired statistical power (default 0.80)
sig.level	a numeric contains the significance level (default 0.05)

Value

Return a numeric containing the appropriate sample size in each group.

Author(s)

Yasuyuki Okumura
Department of Social Psychiatry,
National Institute of Mental Health,
National Center of Neurology and Psychiatry
[e-mail]

References

Cohen J (1988). Statistical power analysis for the behavioral sciences (2nd ed). Hillsdale, NJ: Erlbaum.

See Also

ind.oneway, ind.oneway.second

Examples

##Cohen (1988) ex.8.10
f <- .25
samplesize.etasq(k=4, delta= f^2/(1+f^2), power=.80, sig.level=.05)

Example output

Loading required package: gtools
[1] 45

rpsychi documentation built on May 1, 2019, 10:10 p.m.