STATService a web portal and XML web service for statistical testing of hypotheses

1. STATServicehttp://labs.isa.us.es/apps/statservice José Antonio ParejoMaestre Jorge García Gutierrez Antonio Ruiz Cortés Jose Cristobal Riquelme Santos

2. Motivation Deciding when an algorithm, methodology or treatment is better than another is a key factor for generating scientific knowledge Statistical Testing of Hypotheses is a way to do it

3. Motivation There are two groups of statistical tests: parametric Robust Restricted Applicability  Data must met: Independence Normality Homoscedasticity  USUALLY NOT APPLICABLE (Specifically in Computer Science) non-parametric: The choice when parametric tests are not applicable

5. Contributions StatService: Friedman, Quade and Aligned Friedman non-parametric multiple comparison tests Post-Hoc analyses: Bonferroni-Dunn, Holm, Hotchberg, Hommel, Holland, Rom, Finner, and Li. A web portal that allows importing data and applying the above mentioned tests and post-hoc analyses An XML web service for applying those statistical analyses.

6. Architecture

7. Discussion Fully standards based (other approaches used applets) Free and Open Source (the alternative is commercial) Ubiquitous Interoperable Integration of statistical reasoning in algorithms and other tools (Isa Nepo Paper) Non-Parametric Tests and Post-Hoc analyses (we are pioneer in this both as web portal and web service)

8. Additional Advantages General purpose schema for statistics services Reuse of SCI2S implementation. Refactoring comprises: Encapsulation with a comprehensive and usable Java interfaces for invocation as a library. Extraction of a common interface for all the tests Modification of algorithms for promoting reuse of duplicated source code Creation of automated tests to ensure correctness

9. http://labs.isa.us.es/apps/statservice ¿Preguntas? José Antonio Parejo Maestre japarejo@us.es www.isa.us.es