Chi Squared - Combining Categories
When expected frequencies are too small
This activity covers the issue of what happens when expected frequencies are too small. When this happens, the probabilities no longer follow the chi squared distribution and so the test doesn't work. In this course, you are asked not accept any expected frequencies less than 5 and recognise when this happens you should combine categories.
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Read the notes above and then complete this Combining categories practise exercise to get used to what to do when this situation arises. The exercise also offers the chance to practise calculating probabilities with the normal and binomial distributions.
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