| estimate_impact | Estimate the effect size difference between focal and composite group abilities |
| null_repsd | null_repsd |
| plot_repsd | REPSD Null vs Observed Histogram |
| repsd | repsd |
| repsd_pval | Calculating p-values for repsd |
| timmsData | Sample data from TIMMS |
| timmsDiffic | Sample TIMMS item difficulties |
| timmsDiscrim | Sample TIMMS item discriminations |