Final answer:
The level in the data model that refers to how data is stored in the database is known as the physical level or internal schema, and it's unrelated to levels of measurement like nominal, ordinal, interval, or ratio scales.
Step-by-step explanation:
The level in the data model that describes how the data is being stored in the database is not directly related to the levels of measurement like nominal, ordinal, interval, or ratio scales. Instead, this aspect pertains to the physical level of the database design in the context of data models, like the three-schema approach which comprises the external, conceptual, and internal levels. The physical level, or internal schema, concerns the storage of data on disk, including data structures like indexes, storage files, and so on. It is this level that defines the structural representation of data in the database, specifying the database's efficiency and performance.