A study compares five different genotypes with arbitrary coding. What type of measurement data was used?

In the context of the study comparing five different genotypes, the type of measurement data used is nominal. Nominal data refers to categories or groups that do not have a specific order or ranking among them. In this scenario, the genotypes represent distinct categories of genetic variation without any inherent numerical or ordinal significance.

Each genotype serves as a label for a specific classification and is used to identify these groups for analysis. Since genotypes cannot be quantitatively measured or ordered in terms of magnitude, they fit the definition of nominal data. This is particularly relevant in genetics, where different alleles or genetic types are often simply classified rather than ranked or measured on a scale.

While the other types of measurement data—such as ratio, interval, and ordinal—have specific meanings that imply a form of numerical measurement or ranking, they do not apply in this case because the focus is solely on categorical differences between genotypes, not measurable quantities or ranks.