Null Hypothesis

“Null hypothesis” is a statistical term that basically means that there is an assumption that there is no statistical difference between observations. For example, the null hypothesis would say that any differences between a sample and a population would be due only to random chance. Statistical testing then confirms or denies whether the null hypothesis is actually true or not.

In practice, this might mean that a sample of products is assumed to be consistent with the full population of products (i.e. no statistically significant difference). If the statistics show this not to be true, then the null hypothesis is rejected, meaning that there is some variable in play.

Null hypothesis is denoted as H₀. This is typically pronounced as H-null or H-zero. The complementary term to null hypothesis is alternative hypothesis.