Coefficient alpha is a measure of internal consistency. It is a standard measure of reliability for tests.
Data.frame or matrix object with rows corresponding individuals and columns to items
You can specify any portion of a matrix or data.frame. For instance, if using a data.frame
with numerous variables corresponding to items, one can specify subsets of those items. See examples
alpha <- k/(k-1)*(1-SumSxi/Sx)
where k is the number of items, Sx is the standard deviaton of the total test, and SumSxi is the sum of the standard deviations for each item.
Thomas D. Fletcher email@example.com
Cronbach, L. J. (1951). Coefficient alpha and the internal structure of tests. Psychometrika, 6, 297-334.
1 2 3
Loading required package: multilevel Loading required package: nlme Loading required package: MASS  0.8431428  0.8757325
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.