What term describes the descriptive measurement for a sample that can vary?

The term that describes the descriptive measurement for a sample that can vary is a statistic. Statistics are derived from data collected from a sample, and they can change depending on the specific individuals or observations included in that sample. For example, if you were to take different samples from a larger population and calculate the mean for each, those means (statistics) would likely differ because they are influenced by the particular members of each sample.

Parameters, on the other hand, are fixed values that describe characteristics of a population as a whole and do not change unless the population itself changes. An estimate refers to an approximation of a value, often based on statistics, which adds a layer of uncertainty. The sample mean specifically is a type of statistic focused on measuring the average of a sample. However, when asked for a general term that can apply to various types of measurements derived from samples, the term statistic is the correct choice.