Sample sizes to standard errors calculations

Functions for transforming between standard errors and sample sizes (assuming equal sample sizes per group).

Usage

se_d(d, n)

n_d(d, se)

se_r(r, n)

n_r(r, se)

se_z(n)

n_z(se)

Arguments

d

Cohen's d

n

sample size of the corresponding effect size

se

standard error of the corresponding effect size

r

correlation coefficient

Details

Calculations for Cohen's d, Fisher's z, and log(OR) are based on borenstein2011introductionRoBMA. Calculations for correlation coefficient were modified to make the standard error corresponding to the computed on Fisher's z scale under the same sample size (in order to make all other transformations consistent). In case that a direct transformation is not available, the transformations are chained to provide the effect size of interest.

Note that sample size and standard error calculation for log(OR) is not available. The standard error is highly dependent on the odds within the groups and sample sizes for individual events are required. Theoretically, the sample size could be obtained by transforming the effect size and standard error to a different measure and obtaining the sample size using corresponding function, however, it leads to a very poor approximation and it is not recommended.

References

See also

effect_sizes(), standard_errors()