What is a Null Hypothesis?

The null hypothesis is a statement used to define the expected outcome of a scientific experiment. It is a hypothesis that states that any observed differences between variables in different groups are due to chance alone. In scientific experimentation, the null hypothesis is tested and research is conducted to see if the evidence supports rejection or not.

The null hypothesis has two outcomes when tested: the evidence can either reject the null hypothesis or fail to reject the null hypothesis. It is important to note the distinction between rejecting and failing to reject a null hypothesis. If the evidence fails to reject the null hypothesis, this means that the null hypothesis is accepted. Rejecting a null hypothesis simply means that the evidence supports the alternative hypothesis, or an alternate explanation for the observed change in variables between two or more groups.

Importance of the Null Hypothesis

The null hypothesis is of vital importance in scientific experiments, as it is the basis of the experiment. Without a null hypothesis, it is impossible to determine the validity of an experiment and the evidence it provides. By comparing the null hypothesis to the alternative hypothesis, scientists are able to determine the strength of the evidence and its likelihood of accuracy. Without the null hypothesis, it is difficult to determine the accuracy of evidence and the success of an experiment.

Testing the Null Hypothesis

The null hypothesis is tested using a statistical test that assesses the probability that the observed difference between the experiments occurred by chance. If the statistical test indicates that it is more likely than not that the difference in the variables can be attributed to chance alone, then the null hypothesis is accepted and the evidence is said to fail to reject the null hypothesis. If, however, the statistical test indicates that it is more likely than not that the difference in the variables cannot be attributed to chance alone, then the null hypothesis is rejected and the evidence is said to support the alternative hypothesis.

Ultimately, the null hypothesis is a statement which is used to determine the validity of an experiment and the evidence it provides. By comparing the null hypothesis to the alternative hypothesis, scientists are able to determine the strength of the evidence and its likelihood of accuracy.