phi_domain: Calculate Brown's (1990) short-cut estimate for phi dependability
Description
Calculate Brown's (1990) short-cut estimate for phi dependability
Usage
phi_domain(data, items, total = NULL)
Arguments
data
A data frame of dichotomously scored test items
items
Raw column indices representing the test items or
number of items on the test (see Details).
total
Total score column name of the test (see Details)
Value
The phi estimate for domain score dependability.
Details
When the item-level information is available, Kuder-Richardson 20 is used
as an estimate of alpha. If only the total scores on the test are available and the
number of items is known, Kuder-Richardson 21 is used as an estimate of alpha.