Coefficient alpha is a measure of internal consistency. It is a standard measure of
reliability for tests.
Usage
alpha(x)
Arguments
x
Data.frame or matrix object with rows corresponding individuals and columns to items
Details
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
below.
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.