Search results
Results from the WOW.Com Content Network
Partial regression plots are most commonly used to identify data points with high leverage and influential data points that might not have high leverage. Partial residual plots are most commonly used to identify the nature of the relationship between Y and X i (given the effect of the other independent variables in the model).
In statistics and in particular in regression analysis, leverage is a measure of how far away the independent variable values of an observation are from those of the other observations. High-leverage points , if any, are outliers with respect to the independent variables .
Residuals = residuals from the full model, ^ = regression coefficient from the i-th independent variable in the full model, X i = the i-th independent variable. Partial residual plots are widely discussed in the regression diagnostics literature (e.g., see the References section below).
Thus, for low leverage points, DFFITS is expected to be small, whereas as the leverage goes to 1 the distribution of the DFFITS value widens infinitely. For a perfectly balanced experimental design (such as a factorial design or balanced partial factorial design), the leverage for each point is p/n, the number of parameters divided by the ...
X j·[j] = residuals from regressing X j against the remaining independent variables. Note that the partial leverage is the leverage of the i th point in the partial regression plot for the j th variable. Data points with large partial leverage for an independent variable can exert undue influence on the selection of that variable in automatic ...
In statistics, Cook's distance or Cook's D is a commonly used estimate of the influence of a data point when performing a least-squares regression analysis. [1] In a practical ordinary least squares analysis, Cook's distance can be used in several ways: to indicate influential data points that are particularly worth checking for validity; or to indicate regions of the design space where it ...
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
In regression analysis, the distinction between errors and residuals is subtle and important, and leads to the concept of studentized residuals. Given an unobservable function that relates the independent variable to the dependent variable – say, a line – the deviations of the dependent variable observations from this function are the ...