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# What is a manipulated variable?

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The manipulated variable in an experiment is the independent variable; it is not affected by the experiment's other variables. HowStuffWorks explains that it is the variable the experimenter controls. When there are control and experimental groups, the manipulated variable is the treatment supplied to the experimental group and denied the control group.

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When a scientist graphs the results of an experiment, he graphs the manipulated variable on the x-axis of the graph. One common manipulated variable is time. The scientist controls the time at which he makes the measurements. The y-axis represents the response or dependant variable. Temperature is a common response variable.

Because it is easy to confuse variables in the experiment, About.com offers the mnemonic DRY MIX to help students. It translates: dependant, response, y-axis; manipulated, independent, x-axis. Another way to help keep these values from being confused is through remembering that the independent variable is the "I do" variable.

In addition to manipulated variables and response variables, experiments often include controlled and extraneous variables. Controlled variables are those which the experimenter attempts to keep the same for both groups. Extraneous variables often change the outcome of the experiment in an accidental or unanticipated way. While the experimenter does not graph these variables, it is important for him to keep a record of them in his notes.

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## Related Questions

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In the context of solid three-dimensional geometry, the first octant is the portion under an xyz-axis where all three variables are positive values. Under a Euclidean three-dimensional coordinate system, the first octant is one of the eight divisions determined by the signs of coordinates.

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A constant variable, normally called a controlled variable, is the term for a variable that remains constant throughout an experiment, though other variables may change. An example is the water pressure for a faucet when measuring the amount of water released when the faucet is opened to various increments.

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Experimental research describes the process that a researcher undergoes of controlling certain variables and manipulating others to observe if the results of the experiment reflect that the manipulations directly caused the particular outcome. This type of research differs from a descriptive study, and another one of its important aspects is the use of random assignment.