The null hypothesis, H0, is kappa = 0. The alternative hypothesis, H1, is kappa > 0.
Under the null hypothesis, Z is approximately normally distributed and is used to calculate the p-values.
Where K is the kappa statistic, Var(K) is the variance of the kappa statistic.
See the formulas from Fleiss' kappa statistic (unknown standard)
Assume there are m trials.
The variance of overall kappa with known standards is then equal to the sum of the m variances for overall kappa divided by m2.
Similarly, the variance of kappa for a specific category with known standard equals the sum of the m variances for the kappa for a specific category divided by m2.