Final answer:
The given value describing a sample of professors represents a statistic since it characterizes a subset of the entire group of professors. A parameter, on the other hand, would describe a characteristic of an entire population, such as the mean test score of a professor's entire class.
Step-by-step explanation:
The difference between a statistic and a parameter is that a statistic describes a sample, whereas a parameter describes the entire population. In the situation where a sample of professors is selected and it is found that 55, if 55 represents a characteristic (like an average age, percentage agreeing with a particular stance, etc.) of this specific group, it would be considered a statistic because it is derived from a subset of the entire population of professors.
An example of when a parameter is calculated would be if the average was taken for all members of a population, such as calculating the mean test score for a professor's entire class. If, instead, the U.S. federal government had the resources to survey every single high school senior in the U.S. and found that 50% were planning to attend a four-year college or university, this 50% would be a parameter because it includes the entire population.