Null hypothesis

From Conservapedia

The null hypothesis is the hypothesis that a factor or characteristic of a group is of no consequence. In other words, the null hypothesis is that a factor does not matter.

Many science experiments seek to disprove the null hypothesis as the first step towards proving that a meaningful (alternative) scientific hypothesis is true. Most medical studies, for example, that seek to prove the efficacy of a drug must first rule out the null hypothesis that taking the drug makes no difference.