title: Determining true difference between treatment groups.
abstract: In this article, the author reviews the P value and how it is used to determine true difference of outcome in treatment groups. P value, standard deviation, standard error of the mean, bias, and confidence interval are discussed in common language, with a minimum of jargon and with clinical examples.
authors.affiliation: Internal Medicine Residency Program, Department of Medicine, Stony Brook Medicine - Mather Hospital, Port Jefferson, NY, USA; LCardinal@matherhospital.org.
authors.forename: Lucien J
authors.initials: LJ
authors.lastname: Cardinal
keywords: P value; bias; central limits theorem; normal distribution; parametric statistics; randomization; standard deviation; standard error of the mean; statistics