Final answer:
Longitudinal data is information that is repeatedly collected from the same group of consumers over an extended period of time. It is used in longitudinal research to see how individuals or groups change over time, as opposed to cross-sectional studies, which compare different segments of a population at one time. The correct option is C.
Step-by-step explanation:
The type of data that is collected from the same group of consumers repeatedly over time, with the participants often enrolling as respondents, is referred to as longitudinal data. Longitudinal research involves following a group of research participants for an extended period of time.
This research design is beneficial for observing how individuals or groups change over time. For example, researchers may study the dietary habits of individuals at age 20, then again at 30, 40, and so on, to understand the changes throughout the lifespan of the participants.
Unlike cross-sectional studies, which analyze data at a single point in time from different segments of the population, longitudinal research delves into the same population repeatedly. This allows for observing the progression and development of certain traits or behaviors without the generational cohort effects seen in cross-sectional research.
In essence, longitudinal research provides a dynamic view of how specific variables evolve over time within the same subjects.