Conduct Web experiments using PHP, Part 2
By Paul Meagher2005-03-18
Resources
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- Download the source code for this article.
- To get updates to the SR, CHI and PDL Packages (webexp02.tar.gz) as they are available, go to www.phpmath.com.
- Review necessary concepts for this article in these prerequisite articles:
- "Conduct Web Experiments using PHP, Part 1" sets the framework for the Web offer experiments -- a must-read to get a full appreciation of this article (developerWorks, October 2004).
- "Apply probability models to Web data using PHP" introduces the basic concepts, techniques, and PHP-based tools that define the area of probability modeling and probability distributions (developerWorks, October 2003).
- "Implement Bayesian inference using PHP: Part 2" examines how to use Bayesian inference methods to solve parameter estimation problems (parameter estimations being the process of using sample data to estimate the value of a population or a model parameter (developerWorks, April 2004).
- "Take Web data analysis to the next level with PHP" is a comprehensive overview of how to design Web data analysis that goes beyond simple raw counts (developerWorks, August 2003).
- For a list of references on CDA, take a look at Alan Agresti's site. It includes a link to his book, Categorical Data Analysis, 2nd Ed. (John Wiley and Sons, July 2002).
- For a concise, clear introduction to CDA, read Brian Everitt's The Analysis of Contingency Tables, 2nd Ed. (Chapman and Hall, February 1992).
- Check out Steven Fienberg's site for a list of resources on CDA, including the classic text he co-wrote entitled Discrete Multivariate Analysis: Theory and Practice (MIT Press, June 1977).
- Take an intriguing look into CDA techniques research with the a list of publications on Leo Goodman's site.
- In the paper "CORDS: Automatic Discovery of Correlations and Soft Functional Dependencies," discover how IBM researchers are exploiting the chi-square procedure in the sampling tool CORDS (CORelation Detection via Sampling) (PDF).
- Read up on probability and simulation concepts in "Desert Island Math" (developerWorks, January 2004).
- Learn more about the single-factor anova technique in "ANOVA Statistical Programming with PHP." You can use this quantitative analogue of the single-factor chi-square technique to analyse other aspects of your Web experimental data, such as response time.
- Get a copy of JpGraphs library (which the author used to render the graphs in this article).
- Want to learn more about the Chi Square procedure? Try Chapter 8: Chi-Square Procedures for the Analysis of Categorical Frequency Data of Richard Lowry's e-textbook Concepts and Applications of Inferential Statistics.
- Check out Michael Friendly's page which displays several graphical methods for categorical data analysis.
- Web quality control experiments may generally require a larger N than usability studies. For more on this, read Jakob Neilsen's essay "Card Sorting: How Many Users to Test on sample size selection in usability research.
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| wa-phpexp2.tar.gz | 45.4 KB | FTP | |||||||||
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Tutorial Pages:
» Categorical data analysis
» 2x2 contingency tables
» Sampling model
» Discrete probability distributions
» Binomial sampling model
» Poisson sampling model
» Envisioning your results
» Eliciting your prior distribution
» Model fitting with chi-square
» Null effects model
» Independence model
» Prior model
» DOE explorer
» Explorer output
» Conclusions
» Resources
First published by IBM developerWorks
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