Variables

The elements that describe a situation, an event, an area, apt to change in relation to the context they are supposed to describe. In statistical theory, random variables are defined in the mathematical context of measure theory as measurable functions from a probability space to a measurable space. In applied statistics, a variable is a measurable factor, characteristic, or attribute of an individual or a system. In an experiment, so-called "independent variables" are factors that can be altered or chosen by the researcher. For example, temperature is a common environmental factor that can be controlled in laboratory experiments. "Dependent variables" or "response variables" are those that are measured and collected as data. An independent variable is presumed to affect a dependent one. Variables can be continuous (taking values from a continuum) or discrete (taking values from a defined set). Temperature is a continuous variable, while sex is a discrete variable. This concept of a variable is widely used in the natural, medical and social sciences. In computer science and mathematics, a variable (sometimes called a pronumeral) is a symbol denoting a quantity or symbolic representation. In mathematics, a variable often represents an unknown quantity that has the potential to change; in computer science, it represents a place where a quantity can be stored. Variables are often contrasted with constants, which are known and unchanging.