Testing whether the population proportion might credibly be some pre-determined figure

2 Testing whether the population proportion might credibly be some pre-determined figure 

The above is a perfectly reputable approach, but we are going to introduce a separate test (goodness-of-fit chi-square test). There are two reasons for this  

The chi-square test is one of the oldest and most venerable statistical tests and you will certainly come across cases where other people have used it. You may also want to use it yourself as you know your readers are likely to be familiar with it. 

The chi-square test is flexible (it can be applied in situations where cases are categorized into more than two classes). 

Compares the proportion within a sample with some hypothesized proportion for the population. Is the sample data consistent with the specified proportion  

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