If research groups subjects based on religious and political affiliations, what type of data is being collected?

When research groups subjects based on religious and political affiliations, the type of data being collected is nominal data. Nominal data consists of categories that do not have a specific order or ranking among them. In this case, religious and political affiliations represent distinct categories, such as different religions (e.g., Christianity, Islam, Judaism) or political parties (e.g., Liberal, Conservative, Labour), with each affiliation being a label without inherent numerical value or order.

Nominal data allows for the classification and counting of responses but does not allow for the calculation of averages or meaningful differences, as no value hierarchy is presented. This is a key characteristic that distinguishes nominal data from other types like ordinal, interval, or ratio data.

For instance, while ordinal data would allow for meaningful order (e.g., ranks from best to worst), nominal data is merely about categorization. Interval and ratio data involve numerical values where the differences between values matter (interval data having no true zero, and ratio data having a true zero), which does not apply when categorizing people based on their affiliations. Thus, the correct answer is nominal data as it accurately describes the scenario.