size.ci.biphi {statpsych} | R Documentation |
Sample size for biserial-phi correlation confidence interval
Description
Computes the sample size required to estimate a biserial-phi correlation with desired confidence interval precision. Set the biserial-phi planning value to the smallest absolute value within a plausible range for a conservatively large sample size. The column variable is assumed to be naturally dichotomous and the row variable is assumed to be artificially dichotomous.
Usage
size.ci.biphi(alpha, p1, p2, cor, w)
Arguments
alpha |
alpha level for 1 - alpha confidence |
p1 |
planning value for row 1 marginal proportion |
p2 |
planning value for column 1 marginal proportion |
cor |
planning value for biserial-phi correlation |
w |
desired confidence interval width |
Value
Returns the required sample size
Examples
size.ci.biphi(.05, .2, .5, .3, .4)
# Should return:
# Sample size
# 195
[Package statpsych version 1.8.0 Index]