| center_grand_mean | Center with respect to grand mean |
| center_group_mean | Center with respect to group mean |
| center_mlm | Centering for multilevel analyses |
| composite_score | Composite column |
| dummy_coding | Dummy Coding |
| effect_coding | Effect Coding |
| listwise_deletion | Listwise deletion |
| mlbook_data | mlbook_data |
| recode_item | Recode values of a data frame |
| summarize_missing_values | Count the number of missing values |
| z_scored_grand_mean | Grand mean z-score |
| z_scored_group_mean | Z scored with with respect to the group mean |
| z_scored_mlm | Z-scored for multilevel analyses |
| z_scored_mlm_categorical | Z-scored for multilevel analyses |