cohen.ES {pwr}

Conventional effects size

Description

Give the conventional effect size (small, medium, large) for the tests available in this package

Usage

cohen.ES(test = c("p", "t", "r", "anov", "chisq", "f2"),
    size = c("small", "medium", "large"))

Arguments

test

The statistical test of interest

size

The ES : small, medium of large?

Value

The corresponding effect size

Author(s)

Stephane CHAMPELY

References

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

Examples

## medium effect size for the correlation test
cohen.ES(test="r", size="medium")

## sample size for a medium size effect in the two-sided correlation test
## using the conventional power of 0.80
pwr.r.test(r=cohen.ES(test="r",size="medium")$effect.size,
  power=0.80, sig.level=0.05, alternative="two.sided")