A single data point in a data set is called what?

• A. Parameter
• B. Statistic
• C. Observation
• D. Descriptive measure

Answer: (C)

A single data point is an observation. It’s the value you obtain when you measure or record something about one unit in your study—like one student’s test score or one person's height. All such observations together make up the data set.

Think of the other terms this way: a parameter describes a whole population and is usually unknown; a statistic describes a sample and is used to estimate a parameter; a descriptive measure is any summary value computed from the data (such as the mean or standard deviation). The fundamental building block that feeds all of those is the observation.