collin.fnc: Calculate condition number with intercept included
Description
Calculates the condition number with the intercept included, following
Belsley, Kuh and Welsch (1980).
Usage
collin.fnc(data, colvector)
Arguments
data
A data frame.
colvector
A vector with the column numbers in the data frame for which
the collinearity is to be assessed. Only numeric predictors allowed.
Value
A list with components
svd
Singular value decomposition
cindex
Condition indices
cnumber
The condition number
pi
The phi matrix
References
Belsley, D. A. and Kuh, E. and Welsch, R. E. (1980) Regression
Diagnostics. Identifying Influential Data and Sources of Collinearity, Wiley
Series in Probability and Mathematical Statistics, New York.