CTT {exametrika} | R Documentation |
Classical Test Theory
Description
This function calculates the overall alpha and omega coefficients for the given data matrix. It also computes the alpha coefficient for each item, assuming that item is excluded.
Usage
CTT(U, na = NULL, Z = NULL, w = NULL)
Arguments
U |
U is a data matrix of the type matrix or data.frame. |
na |
na argument specifies the numbers or characters to be treated as missing values. |
Z |
Z is a missing indicator matrix of the type matrix or data.frame |
w |
w is item weight vector |
Value
Returns a list of class c("exametrika", "CTT") containing two data frames:
- Reliability
A data frame with overall reliability coefficients (Alpha and Omega) calculated using different correlation matrices (Covariance, Phi, and Tetrachoric)
- ReliabilityExcludingItem
A data frame showing alpha coefficients when each item is excluded, calculated using different correlation matrices
Examples
# using sample dataset
CTT(J15S500)
[Package exametrika version 1.5.1 Index]