ci.phi: Confidence interval for a phi correlation

In statpsych: Statistical Methods for Psychologists

Confidence interval for a phi correlation

Description

Computes a Fisher confidence interval for a population phi correlation. This function requires the frequency counts from a 2 x 2 contingency table for two dichotomous variables. This measure of association is usually most appropriate when both dichotomous variables are naturally dichotomous.

For more details, see Section 3.4 of Bonett (2021, Volume 3)

Usage

ci.phi(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 phi correlation

• SE - standard error

• LL - lower limit of the confidence interval

• UL - upper limit of the confidence interval

References

\insertRef

Bishop1975statpsych

\insertRef

Bonett2021statpsych

Examples

ci.phi(.05, 229, 28, 96, 24)

# Should return:
#  Estimate     SE    LL    UL
#     0.123 0.0548 0.015 0.229

statpsych documentation built on Jan. 13, 2026, 1:07 a.m.