Chi squared test | definition of chi squared test by Medical dictionary
chi squared test
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chi squared test X2 Statistics A test of association between 2 or more variables, used to identify a linkage between a factor or attribute and an outcome, and determine if the observed values of a variable are significantly different from those expected based on a null hypothesis. See Null hypothesis.
chi squared test A series of statistical procedures used to test how closely the observed result of a trial or a statistical observation corresponds to an expectation, hypothesis or hoped-for result. If, for instance, the expected outcome of a trial is that half the participants will show a particular result, the expected frequency (E) is the total number of participants divided by 2. If Y is the number that show the result and N is the number that do not, then chi squared = (Y-E)2/E + (N-E)2/E. A low chi squared value supports the expectation or hypothesis; a high value rejects it. Tables relating the value to statistical significance are available.