Abstract
In this study, the influence on parameter estimation of observational vec-
tors in a multivariate linear regression model is investigated. A three-stage
method is proposed for this investigation. The first stage involves, with
the help of a linear restriction, the transformation of the multivariate lin-
ear regression model into a restricted multivariate linear regression model.
The second includes the calculation of the difference, via the projection the-
ory, between parameter estimates of the multivariate linear regression model
and that of the restricted multivariate linear regression model. The third
contains the assessment of the influential observations using the generalized
Cook's distance. The first two stages in the study facilitate the calculation
of the difference between parameter estimates, while the third aids the easy
determination of the observational vectors influential on the regression co-
effcients. In the final section of the study, the calculations are illustrated
using a numerical example.