Variable may refer to:
Computer science
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Variable (computer science)
In computer programming, a variable is an abstract storage location paired with an associated symbolic name, which contains some known or unknown quantity of data or object referred to as a '' value''; or in simpler terms, a variable is a named ...
, a symbolic name associated with a value and whose associated value may be changed
Mathematics
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Variable (mathematics)
In mathematics, a variable (from Latin language, Latin ) is a Mathematical symbol, symbol, typically a letter, that refers to an unspecified mathematical object. One says colloquially that the variable ''represents'' or ''denotes'' the object, a ...
, a symbol that represents a quantity in a mathematical expression, as used in many sciences
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Propositional variable, taking the value true or false in mathematical logic
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Random variable
A random variable (also called random quantity, aleatory variable, or stochastic variable) is a Mathematics, mathematical formalization of a quantity or object which depends on randomness, random events. The term 'random variable' in its mathema ...
, a variable in statistics whose value depends on random events
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Categorical variable
In statistics, a categorical variable (also called qualitative variable) is a variable that can take on one of a limited, and usually fixed, number of possible values, assigning each individual or other unit of observation to a particular group or ...
, taking one of a finite number of values in a statistical problem, such as the head or tail result of a tossed coin
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Independent and identically distributed random variables, statistically independent and having the same probability distribution
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Fluent (mathematics), a time-varying quantity as coined by Isaac Newton in his early calculus
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State variable
A state variable is one of the set of Variable (mathematics), variables that are used to describe the mathematical "state" of a dynamical system. Intuitively, the state of a system describes enough about the system to determine its future behavi ...
, used to describe the mathematical "state" of a dynamical system
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Slack variable, inserted to transform an inequality constraint in an optimization problem into an equality
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Dependent and independent variables
A variable is considered dependent if it depends on (or is hypothesized to depend on) an independent variable. Dependent variables are studied under the supposition or demand that they depend, by some law or rule (e.g., by a mathematical function ...
, a variable classified according to whether or not it depends for its value on another variable of interest
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Free variables and bound variables
In mathematics, and in other disciplines involving formal languages, including mathematical logic and computer science, a variable may be said to be either free or bound. Some older books use the terms real variable and apparent variable for f ...
, restricted or otherwise to a specified set of values, such as through a logical quantifier
* Complex variable, the argument or value of a function of a complex number in
complex analysis
Complex analysis, traditionally known as the theory of functions of a complex variable, is the branch of mathematical analysis that investigates functions of complex numbers. It is helpful in many branches of mathematics, including algebraic ...
Physical and social sciences
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Variable (research), a logical set of attributes
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Control variable
A control variable (or scientific constant) in scientific experimentation is an experimental element which is constant (controlled) and unchanged throughout the course of the investigation. Control variables could strongly influence experimental ...
, a measurable entity which is constant (controlled) and unchanged throughout the course of a scientific experiment
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Variable star
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are ...
, a type of astronomical star
Other uses
* "
The Variable", an episode of the television series ''
Lost''
See also
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Hidden variable (disambiguation)
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Variability (disambiguation) Variability is how spread out or closely clustered a set of data is.
Variability may refer to:
Biology
* Genetic variability, a measure of the tendency of individual genotypes in a population to vary from one another
* Heart rate variability, a p ...
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Variance (disambiguation)
{{Disambiguation
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