Abstrakt
Results of a numerical study of the behavior of the instrumental weighted variables estimator - in a competition with two other estimators - are presented. The study was performed under various frameworks (homoscedsticity/heteroscedasticity, several level and types of contamination of data, fulfilled/broken orthogonality condition).
At the beginning the optimal values of eligible parameters of estimatros in question were empirically established. It was done under the various sizes of data sets and various levels of the contamination of data.
These values were then utilized in the numerical study. Its results indicate that instrumental weighted variables are as good as S- and W -estimators and under heteroscedasticity even better.
The weight function of Tukey's type was used.