Resources

• Updates to the probability distribution classes will be available at PHPMath.com. You can download the source for this article.
  
  
• Get the details on the wrapper (and a download of the wrapper) for the two scientific libraries mentioned in this article -- DCDFLIB and RANDLIB.
  
  
• Read "Using Soccer Goals to Motivate the Poisson Process" by Singfat Chu for more on the context and analysis of the problem posed in this article -- developing a model for numbers and time-based frequencies of goals scored in World Cup soccer matches.
  
  
• Explore the author's source of the male height data, "Fitting Percentage of Body Fat to Simple Body Measurements by Roger W. Johnson. This interesting article on the use of multiple regression is from the Journal of Statistics Education.
  
  
• Read about the four lambdas figure (Figure 6) from this article. The figure is courtesy of a fine article, "Distributions" by Paul Bourke which details the following distribution types -- Gaussian (Normal), Poisson, Gamma, Exponential, Rayleigh, and Rice.
  
  
• Read "Make your software behave: Playing the numbers" to discover how to get hardware and software to create a truly random number (quite a task, actually, since they're designed not to produce random results) (developerWorks, April 2000).
  
  
• In "Server clinic: R handy for crunching data," get the details on how to use the sophisticated, open source R software for managing statistical calculations (developerWorks, July 2003).
  
  
• Read "Take Web data analysis to the next level with PHP" for a thorough introduction to Chi Square analysis and its impact on multi-level analysis of Web data.
  
  
• Check out the open source R Project, the central repository on information about R, a language and environment for statistical computing and graphics, similar to the S language.
  
  
• Explore the PEAR Group (PHP Extension and Application Repository) site. PEAR Group is dedicated to providing a structured library of open source code for PHP users; a system for code distribution and package maintenance; a standard style for code written in PHP; the Foundation Classes (PFC) and Extension Code Library (PECL); and a Web site, mailing lists, and download mirrors to support the PHP/PEAR community.
  
  
• Visit the JSci site, the repository for information on JSci. JSci is a set of open source Java packages designed to encapsulate scientific methods and principles in the most natural way possible, to aid in the development of scientific-based software.
  
  
• Visit the IBM General Decimal Arithmetic portal, an ideal place to start to learn how computers represent numbers.
  
  
• Check out the SpamBayes Project which is developing a mostly-client-side, Bayesian anti-spam filter with core code that is a message classifier written in Python.
  
  
• Try this helpful book for learning probability concepts and algorithms, Concepts in Probability and Stochastic Modeling by James J. Higgins and Sallie Keller-McNulty (Duxbury, 1995).