Leverage points :
Leverage points in regression analysis refer to the points in the independent variable space where the changes in the response variable are the greatest. These points are important because they can have a large impact on the model’s predictions and can be used to identify potential outliers in the data.
One example of a leverage point is a point where the independent variable takes on an extreme value. For instance, consider a regression model that predicts the price of a house based on its size and location. In this model, a house that is significantly larger or smaller than the other houses in the sample could be a leverage point because its size is an extreme value. This point could have a large impact on the model’s predictions and could potentially be an outlier.
Another example of a leverage point is a point where the independent variable has a high level of multicollinearity with other variables in the model. Multicollinearity occurs when two or more independent variables are highly correlated with each other. In this case, a change in one variable could have a large impact on the response variable and could potentially be a leverage point.
Overall, leverage points are important because they can have a large impact on the model’s predictions and can be used to identify potential outliers in the data. By identifying these points, analysts can improve the accuracy of their models and make more informed decisions based on the results.