size.ci.spear2 {statpsych} | R Documentation |
Computes the sample size required to estimate a difference in population Spearman correlations with desired confidence interval precision in a 2-group design. Set the correlation planning values to the smallest absolute values within their plausible ranges for a conservatively large sample size.
size.ci.spear2(alpha, cor1, cor2, w)
alpha |
alpha level for 1-alpha confidence |
cor1 |
group 1 Spearman correlation planning value |
cor2 |
group 2 Spearman correlation planning value |
w |
desired confidence interval width |
Returns the required sample size
Bonett DG, Wright TA (2000). “Sample size requirements for estimating Pearson, Kendall and Spearman correlations.” Psychometrika, 65(1), 23–28. ISSN 0033-3123, doi:10.1007/BF02294183.
size.ci.spear2(.05, .8, .5, .2)
# Should return:
# Sample size per group
# 314