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Roy E. Welsch

Researcher at Massachusetts Institute of Technology

Publications -  133
Citations -  14687

Roy E. Welsch is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: Estimator & Regression diagnostic. The author has an hindex of 33, co-authored 126 publications receiving 13941 citations. Previous affiliations of Roy E. Welsch include Singapore–MIT alliance & National Bureau of Economic Research.

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Regression Diagnostics: Identifying Influential Data and Sources of Collinearity

TL;DR: In this article, the authors present a method for detecting and assessing Collinearity of observations and outliers in the context of extensions to the Wikipedia corpus, based on the concept of Influential Observations.
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The Hat Matrix in Regression and ANOVA

TL;DR: A projection matrix known as the hat matrix contains this information and, together with the Studentized residuals, provides a means of identifying exceptional data points and simplifies the calculations involved in removing a data point.
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Algorithm 573: NL2SOL—An Adaptive Nonlinear Least-Squares Algorithm [E4]

TL;DR: The algorithm amounts to a variation on Newton's method in which part of the Hessian matrix is computed exactly and part is approximated by a secant (quasi-Newton) updating method to promote convergence from poor starting guesses.