Viewing the two response variables as two independent ratings of the n subjects, the Kappa coefficient equals +1 when there is complete agreement of the raters. When the observed agreement exceeds chance agreement, the Kappa coefficient is positive, with its magnitude reflecting the strength of agreement. Although unusual in practice, Kappa is negative when the observed agreement is less than chance agreement. The minimum value of Kappa is between 1 and 0, depending on the marginal proportions.
The Likelihood Ratio Chisquare test is computed as twice the negative loglikelihood for Model in the Tests table. Some books use the notation G2 for this statistic. The difference of two negative loglikelihoods, one with wholepopulation response probabilities and one with eachpopulation response rates, is written as follows:
The Pearson Chisquare is calculated by summing the squares of the differences between the observed and expected cell counts. The Pearson Chisquare exploits the property that frequency counts tend to a normal distribution in very large samples. The familiar form of this Chisquare statistic is as follows:
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r and c are row and column sums of P
