ci.cronbach: Confidence interval for a Cronbach reliability

In statpsych: Statistical Methods for Psychologists

Confidence interval for a Cronbach reliability

Description

Computes a confidence interval for a population Cronbach reliability. The point estimate of Cronbach reliability assumes essentially tau-equivalent measurements and the confidence interval assumes parallel measurements.

For more details, see Section 4.19 of Bonett (2021, Volume 1)

Usage

ci.cronbach(alpha, rel, r, n)

Arguments

alpha	alpha level for 1-alpha confidence
rel	estimated Cronbach reliability
r	number of measurements (items, raters, forms)
n	sample size

Value

Returns a 1-row matrix. The columns are:

• Estimate - estimated Cronbach reliability (from input)

• LL - lower limit of the confidence interval

• UL - upper limit of the confidence interval

References

\insertRef

Feldt1965statpsych

\insertRef

Bonett2021statpsych

Examples

ci.cronbach(.05, .85, 7, 89)

# Should return:
# Estimate       SE     LL     UL
#     0.85  0.02457 0.7971 0.8932
 

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