| Title: | Cronbach's Alpha |
|---|---|
| Description: | Cronbach's alpha and various formulas for confidence intervals. The relevant paper is Tsagris M., Frangos C.C. and Frangos C.C. (2013). "Confidence intervals for Cronbach's reliability coefficient". Recent Techniques in Educational Science, 14-16 May, Athens, Greece. |
| Authors: | Michail Tsagris [aut, cre], Constantinos Frangos [aut], Christos Frangos [ctb] |
| Maintainer: | Michail Tsagris <[email protected]> |
| License: | GPL (>= 2) |
| Version: | 0.2 |
| Built: | 2024-12-17 22:03:02 UTC |
| Source: | CRAN |
Cronbach's alpha and various formulas for confidence intervals.
| Package: | fsn |
| Type: | Package |
| Version: | 0.2 |
| Date: | 2024-12-17 |
| License: | GPL-2 |
Michail Tsagris <[email protected]>
Acknowledgments:
Michai Tsagris would like to express his gratitude to Linus Banse for spotting a bug in the function cronfree.ci() when type is "whalen" which has now been fixed.
Michail Tsagris [email protected], Constantinos Frangos [email protected] and Christos Frangos [email protected].
Cronbach L. (1951). Coefficient alpha and the internal structure of tests. Psychometrika, 16(3): 297–334.
Tsagris M., Frangos C.C. and Frangos C.C. (2013). Confidence intervals for Cronbach's reliability coefficient. Recent Techniques in Educational Science, 14-16 May, Athens, Greece. http://www.academia.edu/download/32613010/Cronbachs_alpha.pdf
Confidence intervals for Cronbach's alpha.
cron.ci(x, conf = 0.95, type = "logit", B = 1000)cron.ci(x, conf = 0.95, type = "logit", B = 1000)
x |
A numerical matrix with the data. |
conf |
The confidence level of the interval |
type |
The type of the confidence interval, "logit", "zyl" or "boot". See details for more information. |
B |
This relevant only for the bootstrap based confidence interval. It is the number of bootstrap samples to generate. |
This function contains some confidence intervals for Cronbach's alpha as described in Tsagris, Frangos and Frangos (2013). In particular, the type "zyl" refers to estimating the variance of alpha as suggested by van Zyl J., Neudecker H. and Nel D. (2000) and then constructing the classical confidence interval. The type "logit" computes the logit transformation and then approximates the variance based on the Delta method. This makes use of the variance as computed by van Zyl J., Neudecker H. and Nel D. (2000). Finally, the type "boot" computes BCa confidence intervals.
A confidence interval for the true value of alpha.
Michail Tsagris, Christos Frangos and Constantinos Frangos.
R implementation and documentation: Michail Tsagris [email protected], Christos Frangos [email protected] and Constantinos Frangos [email protected].
Tsagris M., Frangos C.C. and Frangos C.C. (2013). Confidence intervals for Cronbach's reliability coefficient. Recent Techniques in Educational Science, 14-16 May, Athens, Greece. http://www.academia.edu/download/32613010/Cronbachs_alpha.pdf
van Zyl J., Neudecker H. and Nel D. (2000). On the distribution of the maximum likelihood estimator of Cronbach's alpha. Psychometrika, 65(3): 271–280
Efron B. and Tibshirani, R.J. (1993). An introduction to the bootstrap. Chapman & Hall CRC.
Cronbach L. (1951). Coefficient alpha and the internal structure of tests. Psychometrika, 16(3): 297–334.
## silly example x <- as.matrix( iris[1:50, 1:4] ) Cronbach::cron.ci(x)## silly example x <- as.matrix( iris[1:50, 1:4] ) Cronbach::cron.ci(x)
Confidence intervals for Cronbach's alpha wihtout the data.
cronfree.ci(a, p, n, conf = 0.95, type = "kf")cronfree.ci(a, p, n, conf = 0.95, type = "kf")
a |
The Cronbach's alpha. |
p |
The number of items or variables. |
n |
The sample size of the data. |
conf |
The confidence level of the interval |
type |
The type of confidence interval to compute, "kf" or "whalen". See details for more information. |
This function contains some confidence intervals for Cronbach's alpha. The "kf" was described in Tsagris, Frangos and Frangos (2013) and stands for the method of Koning A. and Franses H. P. (2006). The "whalen" stands for the method of Rodriguez and Maeda (2006). The difference with the confidence intervals produced by cron.ci is that with these methods the data are not necessary.
A confidence interval for the true value of alpha.
Michail Tsagris, Christos Frangos and Constantinos Frangos.
R implementation and documentation: Michail Tsagris [email protected], Christos Frangos [email protected] and Constantinos Frangos [email protected].
Tsagris M., Frangos C.C. and Frangos C.C. (2013). Confidence intervals for Cronbach's reliability coefficient. Recent Techniques in Educational Science, 14-16 May, Athens, Greece. http://www.academia.edu/download/32613010/Cronbachs_alpha.pdf
Rodriguez M. C. and Maeda Y. (2006). Meta-analysis of coefficient alpha. Psychological methods, 11(3): 306–322.
Koning A. and Franses H. P. (2006). Confidence intervals for Cronbach's coefficient alpha values. Technical report, Erasmus Research Institute of Management-ERIM.
Cronbach L. (1951). Coefficient alpha and the internal structure of tests. Psychometrika, 16(3): 297–334.
## silly example x <- as.matrix( iris[1:50, 1:4] ) a <- Cronbach::cronbach(x) Cronbach::cronfree.ci(a, 4, 150)## silly example x <- as.matrix( iris[1:50, 1:4] ) a <- Cronbach::cronbach(x) Cronbach::cronfree.ci(a, 4, 150)
Cronbach's alpha.
cronbach(x)cronbach(x)
x |
A numerical matrix with the data. |
This function computes Cronbach's alpha internal reliability coefficient.
The Cronbach's alpha.
Michail Tsagris.
R implementation and documentation: Michail Tsagris [email protected].
Cronbach L. (1951). Coefficient alpha and the internal structure of tests. Psychometrika, 16(3): 297–334.
## silly example x <- as.matrix( iris[1:50, 1:4] ) Cronbach::cronbach(x)## silly example x <- as.matrix( iris[1:50, 1:4] ) Cronbach::cronbach(x)