# Variable

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## Variable

An element in a model. For example, in the model RS&Pt+1 = a + b Tbill t + et, where RS&Pt+1 is the return on the S&P in month t+1 and Tbill is the Tbill return at month t, both RS&P and Tbill are "variables" because they change through time; i.e., they are not constant.

## Variable

Anything that does not have a set value. In basic algebra, a variable is often expressed as "x." Variables in economics and finance may be measures such as GDP, prices, or interest rates. Analysts use complicated equations to determine the value of some variables at the present time and even more complicated equations to predict their possible future values. See also: Regression.

## variable

Something, such as stock prices, earnings, dividend payments, interest rates, and gross domestic product, that has no fixed quantitative value. See also dependent variable, independent variable.
References in periodicals archive ?
Customer behavior type variable is mainly used for getting the information of customers' basic attributes.
Type elaboration can be performed by solving a system of equalities and inequalities between types and type variables generated from the subexpressions of a given program, as specified in Figure 9.
In terms of the polymorphic target language, we regard type variables as ranging over various "store shapes" or state types, so that in a type [Alpha] ??
* "% of stores" type variables in multiplicative (semilog) models (as opposed to 0/1 variables which imply the model is using homogeneous observations)
(Note that [H] is impossible because [K] is not a nested embedding and b [right arrow], fh is not a type variable.) If both are [F], then the induction hypothesis and one use of [F] let us conclude [Psi](e').
let [Alpha] [not element of] V be a fresh type variable
Note that we do not allow the type variable binders [[bar]X] to be inferred.
If a polymorphic type variable [Alpha] has the 32-bit kind, then objects of type [Alpha] can be passed in general-purpose registers, and tuple offsets may be computable for fields appearing after a field of type [Alpha].
Polmorphic types of the form [inverted]A[Alpha] [is less than]: [Rho].[Sigma] constrain instantiations of a type variable [Alpha] to the set of types described by [Rho].
We can also use <x>, [([Lambda]x.e)e'], [[Lambda]x.e], [e], [e'] as type variables, and for a type system such as simple types where there is no nontrivial subtyping between function types, we get, among others, the following constraints on type correctness:
In comparison, Johnson and Walz's unification algorithm [Johnson and Walz 1986] reports that the "false" expression must have the type int, because it selects the most "popular" types if multiple, conflicting types are bound to a type variable.
[Sigma.sub.n], also written [k.sup.f??]) followed by either a single type variable ([Alpha]) or the empty type ([Phi]):

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