Illustration of bee on flowers

The null hypothesis

A hypothesis is an explanation you can test

It’s human nature to look for patterns and draw conclusions from what we observe – for example, to argue that there is a link between x and y.

However, science can actually never prove anything with absolute certainty. Instead, researchers assume that no link exists and explore how likely it is that they would still see the same result because of chance or other unknown factors.

In science, a hypothesis is the explanation you think is behind an explanation you think is behind an observation. To show a scientific hypothesis to be true, you actually need to show that the null hypothesis – a ‘non-event’ where the effect is not seen – is false. Statistical analysis can then be used to assess the support for the alternative hypothesis. For example, you might think that bumblebees prefer one colour flower over another. In this case, your null hypothesis (H0) is ‘There is no difference in the number of visits to each colour of flower’, and the alternative hypothesis (H1) is ‘There is a difference in the number of visits to each colour of flower’.

Lead image:

Illustration copyright Glen McBeth. Please do not reuse without permission from the illustrator.

About this resource

This resource was first published in ‘Number Crunching’ in June 2013.

Statistics and maths
Number Crunching
Education levels:
16–19, Continuing professional development