Definition: The null hypothesis is the proposition that implies no effect or no relationship between phenomena. The null hypothesis is popular because it can be tested and found to be false, which then implies there is a relationship between the observed data.
Also Known As: H0, no-difference hypothesis
"Hyperactivity is unrelated to eating sugar." is an example of a null hypothesis. If the hypothesis is tested and found to be false, using statistics, then a connection between hyperactivity and sugar ingestion may be indicated.