In the context of data, what does the term 'parameter' refer to?

The term 'parameter' refers to a summary statistic of a population, which embodies essential characteristics of that entire group. Parameters are typically used in statistics to describe attributes like the mean, median, proportion, or standard deviation that belong to the whole population under study.

In connection to the other options, the average of sample data pertains specifically to a sample statistic, rather than a parameter, as it only represents a subset of the larger population. Similarly, a characteristic of a sample set also describes a sample statistic, not a population. Lastly, a measure that remains constant is not aligned with the concept of a parameter, which can vary depending on the population being analyzed. Understanding this distinction is crucial for proper data analysis and ensuring clarity around population versus sample characteristics.