ABSTRACT
Statistics and probability come up frequently in analyzing hydrologic data, and they are useful in two ways: description, and inference. Statistics summarize and describe temporal and spatial data. Statistics such as the mean and standard deviation are commonly used to summarize a sample of data. The chapter focuses on the question of the constancy of the statistical properties of a hydrologic process over time. Two terms are used in the hydrologic literature to describe constancy over time – stationary and homogeneous. Dispersion refers to how data are distributed around their central location. One way to measure the spread of the data is the range. The chapter plays a very important role in hydrology because they represent basic techniques, skills and concepts that are used again and again in analyzing hydrologic phenomena.
