TetrachoricCorrelationMatrix {exametrika} | R Documentation |
Tetrachoric Correlation Matrix
Description
Calculates the matrix of tetrachoric correlations between all pairs of items. Tetrachoric Correlation is superior to the phi coefficient as a measure of the relation of an item pair. This function is applicable only to binary response data.
Usage
TetrachoricCorrelationMatrix(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 |
... |
Internal parameters for maintaining compatibility with the binary data processing system. Not intended for direct use. |
Value
A matrix of tetrachoric correlations with exametrika class. Each element (i,j) represents the tetrachoric correlation between items i and j. The matrix is symmetric with ones on the diagonal.
Note
This function is implemented using a binary data compatibility wrapper and will raise an error if used with polytomous data.
Examples
# example code
TetrachoricCorrelationMatrix(J15S500)