Which statistic represents the middle observation when data are ordered from smallest to largest?

• A. Median
• B. Mean
• C. Mode
• D. Range

Answer: (A)

Line up the data from smallest to largest and pick the central value. That statistic represents the middle observation—the median. It serves as a central point of the data and is less influenced by extreme values than the mean, which makes it a reliable measure of central tendency when the data are skewed or contain outliers. For an odd number of observations, there’s a single middle value; for an even number, the usual convention is to average the two middle values, which still centers the data. In contrast, the mean is the arithmetic average, the mode is the most frequent value, and the range only describes how spread out the data are.