20 slides: Cohen's kappa middle 95% of studies 0.13 to 0.67; quadratic-weighted kappa 0.68 to 0.93
40 slides: Cohen's kappa middle 95% of studies 0.21 to 0.59; quadratic-weighted kappa 0.74 to 0.91
80 slides: Cohen's kappa middle 95% of studies 0.27 to 0.54; quadratic-weighted kappa 0.78 to 0.89