Null Hypothesis (2 of 4)

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It should be stressed that researchers very frequently put forward a null hypothesis in the hope that they can discredit it. For a second example, consider an educational researcher who designed a new way to teach a particular concept in science, and wanted to test experimentally whether this new method worked better than the existing method. The researcher would design an experiment comparing the two methods. Since the null hypothesis would be that there is no difference between the two methods, the researcher would be hoping to reject the null hypothesis and conclude that the method he or she developed is the better of the two.

The symbol H0 is used to indicate the null hypothesis. For the example just given, the null hypothesis would be designated by the following symbols:

H0: µ1 - µ2 = 0

or by

H0: μ1 = μ2.

The null hypothesis is typically a hypothesis of no difference as in this example where it is the hypothesis of no difference between population means. That is why the word "null" in "null hypothesis" is used -- it is the hypothesis of no difference.
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