Meaning of P-value

Abstract

In medical and dental research, we are usually interested in understanding the real effect of two or more interventions (such as drugs or surgeries) on an outcome (such as signs and symptoms of a disease). To test such effects, we typically establish two hypotheses: the null hypothesis and the alternative hypothesis. In the null hypothesis, the researcher assumes that there is no difference between the two interventions on the outcome, while the alternative hypothesis assumes that a difference exists. We collect, clean, and analyze data using an appropriate statistical test. The test produces a p-value, which ranges from 0 to 1. The researcher sets a significance level (usually p ≤ 0.05).A small p-value (typically ≤ 0.05) suggests there is enough evidence to reject the null hypothesis in favor of the alternative hypothesis. Conversely, a larger p-value indicates a lack of evidence to reject the null hypothesis.