Standard Article

P Value

Statistical Theory and Methods

  1. Mohan Delampady

Published Online: 15 SEP 2006

DOI: 10.1002/9780470057339.vap001

Encyclopedia of Environmetrics

Encyclopedia of Environmetrics

How to Cite

Delampady, M. 2006. P Value. Encyclopedia of Environmetrics. 4.

Author Information

  1. Indian Statistical Institute, India

Publication History

  1. Published Online: 15 SEP 2006


The P value is one of the tools from classical statistics that is used very widely in applied sciences. It is also one of the concepts that is highly misunderstood and misused. The basic idea behind Fisher's original (1925) definition of P value did have a great deal of appeal: it is the probability under a (simple) null hypothesis of obtaining a value of a test statistic that is at least as extreme as that observed in the sample data.