Table : TABLE 18-7. Organizing Data for a Mann–Whitney U Test To conduct a Mann–Whitney U test, we first organize the data. We organize the raw scores from highest to lowest in a single column, then rank them in an adjacent column. Notice that when scores are tied, we average the ranks of the two or three tied scores. The next column includes the group to which each country belongs—in this case, a recently communist country (C) or a noncommunist (NC) country. The last two columns separate the ranks by group.