size.ci.stdmean.ps {statpsych} | R Documentation |
Computes the sample size required to estimate two types of population standardized mean differences (unweighted standardizer and single group standardizer) with desired confidence interval precision in a paired-samples design. For a conservatively large sample size, set the standardized mean difference planning value to the largest value within a plausible range and set the Pearson correlation planning value to the smallest value within a plausible range.
size.ci.stdmean.ps(alpha, d, cor, w)
alpha |
alpha level for 1-alpha confidence |
d |
planning value of standardized mean difference |
cor |
planning value of correlation between measurements |
w |
desired confidence interval width |
Returns the required sample size for each standardizer
Bonett DG (2009). “Estimating standardized linear contrasts of means with desired precision.” Psychological Methods, 14(1), 1–5. ISSN 1939-1463, doi: 10.1037/a0014270.0
size.ci.stdmean.ps(.05, 1, .65, .6) # Should return: # Sample Size # Unweighted standardizer: 46 # Single group standardizer: 52