Wednesday, May 12, 2010

What does independent variable, dependent variable, constant and control means?

wikipedia, google, and other websites doesn't helpWhat does independent variable, dependent variable, constant and control means?
The distinction between these two types of variables is whether the variable regress on another variable or not. Like in a linear regression the dependent variable (DV) regresses on the independent variable (IV), meaning that the DV is being predicted by the IV. Within SEM modelling this means that the exogenous variable is the variable that another variable regresses on. Exogenous variables can be recognized in a graphical version of the model, as the variables sending out arrowheads, denoting which variable it is predicting. A variable that regresses on a variable is always an endogenous variable even if this same variable is used as an variable to be regressed on.

A constant is something that does not change, over time or otherwise: a fixed value. In most fields of discourse the term is an antonym of ';variable';, but in mathematical parlance a mathematical variable may sometimes also be called a constant.

Controlling for a variable is the act of deliberately varying the experimental conditions in order to take a single variable into account in the prediction of the outcome variable. Controlling tends to reduce the experimental error. A control is something that does not change in the experiment.What does independent variable, dependent variable, constant and control means?
y=3x^2; (x),is the independent variable it determines the value of (y)

Dependent variable; y=3x^2, A variable in a functional relation whose value is determined by the value assumed by other variables in the relation as (y) in the above relation.

Constant; A quantity assumed to be unchanged throughout a given discussion.

Control; to test or verify a problem is correct by a parallel problem or other standard of comparison.
Well for example:

in the equation



x represents the independent variable because we are solving for y

x can be any number

y represents the dependent variable because y depends on what x is

if x was equal to one y would equal six

the constant in this equation is 4 because it never changes

it does not have a variable with it therefore it remains 4

as for control I don't know what you mean.
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