What purposes does the null hypothesis serve?

First,the null hypothesis acts as a starting point,since it is the state of affairs that is accepted as true in the absence of any other information.The second purpose of the null hypothesis is to provide a benchmark against which observed outcomes can be compared to see how likely it is that these outcomes are due to some other factor.The null hypothesis helps to define a range within which any observed differences between groups can be attributed to chance or due to something other than chance.