Developers: Dr. John Behrens and Dr. Chong Ho Yu Software: Xlisp-Stat Media: Interactive simulations Description: Statistical power, which involves the relationship among alpha, beta, effect size, and sample size, are very difficult to understand. This simulation written in Xlisp-Stat enables students to visually explore the inter-relationships among those variables in a "what-if" manner. To be specific, in the simulation users can manipulate effect size, sample size, and alpha level from the lower panels, and the corresponding changes of power and beta will appear on the upper window. The value of power is printed on the upper left box whenever an input is made. Alternatively, you can view an animated demo of the program. You may also move the mouse over different parts of the following graph to learn about the basic components of statistical power analysis. Instructions for downloading and running the program: Download the compressed program. The archive should be decompressed by your web browser. Click open Xlisp-stat 50 PPC in the folder R-code. Type (menu) at the > prompt (The bracket must be included). Choose Power Simulation from the popup menu. Choose the indicator(s) (e.g. power, beta...etc) on the right panel. Manipulate effect size, sample size, and alpha level on the left. Navigation Multimedia Menu Simplified Navigation Table of Contents Search Engine Contact