MTH-416, REGRESSION ANALYSIS Lecture 6: Chapter6-Regression-Diagnostic for Leverage and Influence

• School: Indian Institute of Technology - IIT Kanpur
• Department: Mathematics
• Course: MTH-416, REGRESSION ANALYSIS
• Professor: All

Document Summary

The location of observations in x -space can play an important role in determining the regression coefficients. Consider a situation like in the following yi. The point a in this figure is remote in regression line passing through the rest of the sample points. It is an unusual x -value and may control certain model properties. space x from the rest of the sample but it lies almost on the. This point does not affect the estimates of the regression coefficients. 2r , standard errors of regression coefficients etc. Now consider the point b following figure: y i. This point has a moderately unusual x -coordinate and the y -value is also unusual. It has a noticeable impact on the model coefficients. It pulls the regression model in its direction. Sometimes a small subset of data exerts a disproportionate influence on the model coefficients and properties.