Question

Why do we test the null hypothesis and not our research hypothesis?

Answer 1

Actually we should know what is null hypothesis and what is research hypothesis?

Null Hypothesis is simply denoted by H0---- It is the hypothesis in which we can not see any significant difference between two populations.

And Alternative or Research hypothesis is denoted as H1.--- this hypothesis always contradicts the null hypothesis. So from this statement we can understand that something diffrent may be happened which forces to reject the statement of null hypothesis.

Now our Question is why do we test the null Hypothesis instead of research hypothesis?

we have mentioned that Null hypothesis always deals with an equivalent statements by which we can fix a particular value for a population characteristics. Or if we try to compare two population characteristics without knowing anything we can deliberately claim that two population characteristics are equal or about to be equal. So What is the benefit of of null hypothesis? Yeah .. this is a naive and simple statement by which we can assume an equivalent statement. We don't need to know whether there exists an uniequality.

If we are able to reject the null hypothesis then it is clear to us that the alternative claim is true. And we can reach at our suitable conclusion. That's why we test hypothesis under null hypothesis not under alternative or reserach hypothesis.