size.ci.ratio.prop2 {statpsych} | R Documentation |
Computes the sample size in each group (assuming equal sample sizes) required to estimate a ratio of proportions with desired confidence interval precision in a 2-group design.
size.ci.ratio.prop2(alpha, p1, p2, r)
alpha |
alpha level for 1-alpha confidence |
p1 |
planning value of proportion for group 1 |
p2 |
planning value of proportion for group 2 |
r |
desired upper to lower confidence interval endpoint ratio |
Returns the required sample size per group
size.ci.ratio.prop2(.05, .2, .1, 2) # Should return: # Sample size per group # [1,] 416