# Principles of Data Reduction >[!Abstract] In [[self.stats/Statistics]] and [[Probability Theory]], an experimenter might wish to summarize the information in a sample by determining a few key features of the sample values. This is usually done by computing statistics, i.e. functions of the sample. For example, the sample mean, the sample variace, the largest observaion, and the smallest observation are four statistics that might be used to summarize some key features of the sample. >[!Note] Here is a list of summary statistics: >- [[Likelihood]]