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chi square (redirected from ? 2)
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chi square (c2) a statistical test for use with nominal data (see CRITERIA AND LEVELS OF MEASUREMENT). The EXPERIMENTAL HYPOTHESIS predicts how many subjects in each group being tested will fall into certain categories if there are no differences between the groups, and the chi-square test compares the observed frequencies with the expected frequencies. The larger the difference between the observed and expected frequency, the more likely that there is a statistically significant difference between the categories.