prec_cronb: Sample size or precision for Cronbach's alpha

In CTU-Bern/presize: Precision Based Sample Size Calculation

Sample size or precision for Cronbach's alpha

Description

prec_cronb returns the sample size or the precision for the given Cronbach's alpha.

Usage

prec_cronb(k, calpha, n = NULL, conf.level = 0.95, conf.width = NULL)

Arguments

k	number of measurements/items.
calpha	desired Cronbach's alpha.
n	sample size.
conf.level	confidence level.
conf.width	precision (the full width of the confidence interval).

Details

Exactly one of the parameters n or conf.width must be passed as NULL, and that parameter is determined from the other.

Sample size or precision is calculated according to the formula & code and provided in Bonett and Wright (2014).

n is rounded up to the next whole number using ceiling.

Value

Object of class "presize", a list of arguments (including the computed one) augmented with method and note elements.

References

Bonett, D. G. and Wright, T. A. (2015) Cronbach's alpha reliability: Interval estimation, hypothesis testing, and sample size planning J. Organiz. Behav., 36, pages 3– 15. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1002/job.1960")}. # k= number of items

Examples

# calculate confidence interval width...
prec_cronb (k=5,calpha=0.7,n= 349,conf.level= 0.95, conf.width= NULL)
# calculate N required for a given confidence interval width...
prec_cronb (k=5,calpha=0.7,n= NULL,conf.level= 0.95, conf.width= 0.1)

CTU-Bern/presize documentation built on Nov. 2, 2024, 10:54 p.m.