Quite often we can find the critical value for a given test and also this can be used an alternative method of testing a hypothesis. In fact I generally prefer this method.

In the first of these tutorials on critical values I run through the following example which will illustrate this method.

A manufacturer claims that 2 out of 5 people prefer Soapy Suds washing powder over any other brand. For a sample of 25 people, only 4 people are found to prefer Soapy Suds. Is the manufacturer’s claim justified?
Test at the 5% level of significance.

Hypothesis testing critical value method for a Binomial Distribution example 1 : ExamSolutions - youtube Video