In many sciences, including ecology, medicine, and psychology, null hypothesis significance testing (NHST) is the primary means by which the numbers comprising the data from some experiment are translated into conclusions about the question(s) that the experiment was designed to address. This entry first provides a brief description of NHST, and within the context of NHST, it defines the most common incarnation of a null hypothesis. Second, this entry sketches other less common forms of a null hypothesis. Third, this entry articulates several problems with using null hypothesis-based data analysis procedures.
Null Hypothesis Significance Testing and the Null Hypothesis
Most experiments entail measuring the effect(s) of some number of independent variables on some dependent variable.
An Example Experiment
In the simplest sort of experimental design, one measures the effect ...