Texas A&M University (TAMU) PHLT 305 Epidemiology in Public Health Exam 1 Practice Test

Dispersion describes how spread out the data are, and the standard deviation is the descriptor that quantifies this spread most directly. It measures how far, on average, observations lie from the mean, using the same units as the data, which makes it easy to interpret in the context of the dataset. Since it’s built from the squared deviations, it reflects the overall variability across all data points and is the most commonly used measure of spread in many analyses.

Variance is related but expressed in squared units, which makes interpretation less intuitive. The range only captures the gap between the minimum and maximum values and can be heavily influenced by outliers, providing a coarse sense of spread. The mean describes a central tendency, not how variable the data are.