ci.tetra {statpsych} | R Documentation |
Confidence interval for a tetrachoric correlation
Description
Computes a confidence interval for an approximation to the tetrachoric correlation. This function requires the frequency counts from a 2 x 2 contingency table for two dichotomous variables. This measure of association assumes both of the dichotomous variables are artificially dichotomous. An approximate standard error is recovered from the confidence interval.
Usage
ci.tetra(alpha, f00, f01, f10, f11)
Arguments
alpha |
alpha level for 1-alpha confidence |
f00 |
number of participants with y = 0 and x = 0 |
f01 |
number of participants with y = 0 and x = 1 |
f10 |
number of participants with y = 1 and x = 0 |
f11 |
number of participants with y = 1 and x = 1 |
Value
Returns a 1-row matrix. The columns are:
Estimate - estimate of tetrachoric approximation
SE - recovered standard error
LL - lower limit of the confidence interval
UL - upper limit of the confidence interval
References
Bonett DG, Price RM (2005). “Inferential methods for the tetrachoric correlation coefficient.” Journal of Educational and Behavioral Statistics, 30(2), 213–225. ISSN 1076-9986, doi:10.3102/10769986030002213.
Examples
ci.tetra(.05, 46, 15, 54, 85)
# Should return:
# Estimate SE LL UL
# 0.5135167 0.09301703 0.3102345 0.6748546