“What role does the null hypothesis REALLY play in the scientific process?”

13 Oct

3rd blog already, how time flies! This week I was pretty stuck for ideas on what to write my blog on, so I resorted to looking at the list of possible blog topics. I have been puzzled over the need for a null hypothesis since writing my ‘Is Psychology a Science’ assignment, so I have decided to debate it.

In science, research must follow the rule of the null hypothesis. This is the assumption that all assertions are false, unless they have been proven, with evidence, to be correct. So in other words, everything that hasn’t been backed up with evidence is considered untrue. The null hypothesis is the opposite of what the experimenter predicts, that there is no relationship between the two variables. The Alternate hypothesis is the null hypothesis’s rival. The alternate hypothesis would assume that the assertion was true.

For example:

Hypothesis– The plate is hot due to it being in the sun.

Null hypothesis– The plate being hot is not due to it being in the sun.

Alternate hypothesis– The plate is hot due to it being in the sun.

But why do scientists actually use the null hypothesis? They say that the only way to support a hypothesis is to disprove a null hypothesis! Rather than trying to prove that the alternate hypothesis is correct, you must find the null hypothesis to be wrong! This means that we would have to look for other reasons that the plate could be hot, rather than it being in the sun. Doesn’t that sound all very complicated and unnecessary really?  Why cant we just find evidence for a hypothesis being correct?

I think that the null hypothesis is mainly used to act as a safety guard. It helps to reduce bias in experiments. Researchers will be inclined to be bias towards the results that they would like in their experiments. But if they were to set out to prove or disprove a null hypothesis, would they be less biased? It helps to cancel out other variables and ensures that the researcher has covered all possible variables in their experiment.

I’m still finding this all a little confusing, so please criticise my ideas as to why the null hypothesis is important!



2 Responses to ““What role does the null hypothesis REALLY play in the scientific process?””

  1. ihmsl October 13, 2011 at 7:46 pm #

    Hey Jess, yes looks like you have grasped the concept of hypothesis and null hypothesis. In simple terms the hypothesis is the researchers prediction, whilst the null hypothesis rejects the hypothesis. Its important to note that a a null hypothesis can never be accepted, it is rather what the researcher looks to disprove.

    For example the Hypothesis may be: Depression in women is higher during the winter season.

    Whilst the null hypothesis would be: Depression in women is no higher during the winter season.

    Now in the event of the researcher finding the hypothesis to be true at a significant statistical level, then the researcher would reject the null hypothese and accept the hypothesis with a high degree of confidence.

  2. hannahsmith93 October 17, 2011 at 6:15 pm #

    Hypotheses, particularly the null hypothesis are very important in psychology both for the reasons you mentioned in your blog and also they are crucial within the Hypothetico-Deductive model. Which is the process by which a theory or hypothesis is tested and the scientific theory is adapted. It could be viewed that hypotheses are important factors in making psychology more scientific, as a null hypothesis, and testing is pivotal in the falsification of psychological theory, which Popper believed was crucial if psychology is ever going to be viewed as a science.

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