compute_CI {Indicator}

Calculation of Condition Indices

Description

Diagnosis of collinearity in matrix X

Usage

compute_CI(matrix)

Arguments

matrix

a matrix of data where rows = observations and columns = variables

Details

Collinearities can inflate the variance of the estimated regression coefficients and numerical stability. The condition indices are calculated by the eigenvalues of the crossproduct matrix of the scaled but uncentered explanatory variables. Indices > 30 may indicate collinearity

Value

It returns the condition index of the matrix

References

Belsley, D. , Kuh, E. and Welsch, R. E. (1979), Regression Diagnostics: Identifying Influential Data and Sources of Collinearity, John Wiley (New York)

Examples

data("Education")
compute_CI(Education)