Skip to contents

Confidence interval for a 2-group reliability difference

Source: R/statpsych2.R
ci.rel2.Rd

Computes a 100(1 - alpha)% confidence interval for a difference in population reliabilities in a 2-group design. This function can be used with any type of reliability coefficient (e.g., Cronbach alpha, McDonald omega, intraclass reliability). The function requires a point estimate and a 100(1 - alpha)% confidence interval for each reliability as input.

For more details, see Section 2.15 of Bonett (2021, Volume 4)

Usage

ci.rel2(rel1, ll1, ul1, rel2, ll2, ul2)

Arguments

rel1

estimated reliability for group 1

ll1

lower limit for group 1 reliability

ul1

upper limit for group 1 reliability

rel2

estimated reliability for group 2

ll2

lower limit for group 2 reliability

ul2

upper limit for group 2 reliability

Value

Returns a 1-row matrix. The columns are:

  • Estimate - estimated reliability difference

  • LL - lower limit of the confidence interval

  • UL - upper limit of the confidence interval

References

Bonett DG (2021). Statistical Methods for Psychologists https://dgbonett.sites.ucsc.edu/.

Bonett DG, Wright TA (2015). “Cronbach's alpha reliability: Interval estimation, hypothesis testing, and sample size planning.” Journal of Organizational Behavior, 36(1), 3–15. ISSN 08943796, doi:10.1002/job.1960 .

Examples

ci.rel2(.4, .35, .47, .2, .1, .32)
#>  Estimate   LL     UL
#>       0.2 0.07 0.3221

# Should return:
# Estimate   LL     UL
#      0.2 0.07 0.3221