DEFINITION of 'Chi Square Statistic'
A measurement of how expectations compare to results. The data used in calculating a chi square statistic must be random, raw, mutually exclusive, drawn from independent variables and be drawn from a large enough sample. For example, the results of tossing a coin 100 times would meet these criteria.
INVESTOPEDIA EXPLAINS 'Chi Square Statistic'
As a simple example of how to calculate and use the chi square statistic, consider tossing a coin 100 times. The expected result of tossing a fair coin 100 times is that heads will come up 50 times and tails will come up 50 times. The actual result might be that heads comes up 45 times and tails comes up 55 times. The chi square statistic will show any discrepancies between the expected results and the actual results.
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