What is a 'null hypothesis'?

Question

Could you explain in layman terms please because Ive looked on the web and I cant seem to find a simple explanation to apply to my biology homework!

Answer 1

well say you were looking to see if there was a correlation between height and weight (for example) the null hypothesis would be 'there is no correlation between height and weight', then you would have to make a real hypothesis on what you really think. Basically you are trying to prove the null hypothesis wrong.

Answer 2

This is from Biology Online:
null hypothesis

The assumption that any observed difference between two samples of a statistical population is purely accidental and not due to systematic causes.

Answer 3

the null hypothesis according to my biology book is....a null hypothesis is used to examine the results of scientific investigations and is based on the assumption that there will be NO significant difference between sets of observations and that any difference found would be due to chance alone.

Answer 4

Although it was originally proposed to be any hypothesis, in practice it has come to be identified with the "nil hypothesis", which states that "there is no phenomenon", and that the results in question could have arisen through chance.

Answer 5

when there is nothing to be found. ie, if you did an experiment and you found that there was no correlation between your two subjects, it would be classed as a null hypothesis

Answer 6

You could not have looked very hard, then.

Look here ---> http://www.biochem.northwestern.edu/holmgren/Glossary/Definitions/Def-N/null_hypothesis.html

Answer 7

who can not exist?