Detailed Instructions: Given a scientific passage and an answer, generate a question for the given answer.
Q: Passage: The girls in the picture above make up a small samplethere are only four of them. In scientific investigations, samples may include hundreds or even thousands of people or other objects of study. Especially when samples are very large, it's important to be able to summarize their overall characteristics with a few numbers. That's where descriptive statistics come in. Descriptive statistics are measures that show the central tendency, or center, of a sample or the variation in a sample. Answer: samples
A:
In scientific investigations, descriptive statistics are useful for summarizing the characteristics of large what?