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exametrika (version 1.6.0)

ITBiserial: Item-Total Biserial Correlation

Description

The Item-Total Biserial Correlation computes the biserial correlation between each item and the total score. This function is applicable only to binary response data.

This correlation provides a measure of item discrimination, indicating how well each item distinguishes between high and low performing examinees.

Usage

ITBiserial(U, na = NULL, Z = NULL, w = NULL)

# S3 method for default ITBiserial(U, na = NULL, Z = NULL, w = NULL)

# S3 method for binary ITBiserial(U, na = NULL, Z = NULL, w = NULL)

Value

A numeric vector of item-total biserial correlations. Values range from -1 to 1, where:

  • Values near 1: Strong positive discrimination

  • Values near 0: No discrimination

  • Negative values: Potential item problems

Arguments

U

Either an object of class "exametrika" or raw data. When raw data is given, it is converted to the exametrika class with the dataFormat function.

na

Values to be treated as missing values.

Z

Missing indicator matrix of type matrix or data.frame. Values of 1 indicate observed responses, while 0 indicates missing data.

w

Item weight vector specifying the relative importance of each item.

Examples

Run this code
# using sample dataset
ITBiserial(J15S500)

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