Contrasts

Contrasts (Analysis of Variance) (GWU EMSE-271)
Index | Topics (Logical Lectures) | Lectures | Problems | Readings | Nomenclature | Concepts

"In statistics, particularly analysis of variance, a **contrast** is a linear combination of two or more factor level means (averages) whose coefficients add up to zero. A simple contrast is the difference between two means.

"Contrasts are sometimes used to compare mixed effects." - [|Wikipedia] - EMSE 271, Fall 2009, Slide 301

"Contrast coefficient must be chosen prior  to running the experiment and prior to examining the data. Otherwise bias in Type I error may occur." - EMSE 271, Fall 2009, Slide 304

[|Example of Orthogonal Contrasts] - [|Analysis and Variance and Covariance], Doncaster and Davey


 * Sources:**
 * Contrast (statistics). (2009, November 18). In //Wikipedia, The Free Encyclopedia//. Retrieved 15:38, December 11, 2009, from []
 * Analysis of Variance and Covariance, .... TBR ..., Retrieved 11:59, January 10, 2010, form []
 * EMSE 271, Fall 2009