What's the independent and dependent variable in a scientific controlled experiment? Please give examples?

http://en.wikipedia.org/wiki/Dependent_v鈥?/a>


http://en.wikipedia.org/wiki/Independent鈥?/a>


Example: http://en.wikipedia.org/wiki/Independent鈥?/a>





The independent variable is changed or altered or somehow manipulated by the experimenter and as a result the dependent variable changes.What's the independent and dependent variable in a scientific controlled experiment? Please give examples?
The dependent variable is what you are measuring for a change when you vary the independent's variable value.





Example the yeild of a chemical in a reaction varies with temperature, but you don't know in what way.





So you fix the time, and do several experiments at various temperatures, then measure the amount produced at each temperature.





Sometimes you are surprised and find out that the independent variable does not have an effect on the dependent variable.What's the independent and dependent variable in a scientific controlled experiment? Please give examples?
The independent variable is the one you can control. The dependent is the one affected by changing that controlled variable.





Lets say you wanted to know the relation between tire inflation pressure and gas mileage. The independent variable is the pressure. The dependent would be the gas mileage.





BTW - I don't know why experimentation is still being taught this way. Statistical Design of Experiments allows you to vary multiple independent variables which give you information on interplay between those variables.
Independent variable : The variable whose value can be fixed or taken at will





Dependent : One whose value depends on the independent variable.
A(x,y)=aX^2+bxy+cY^2


Here is an example of A(x,y) which a dependent variable. it depends on two independent variables x%26amp;y.We have chosen a second degree equation. You could go to a higher degree to increase the complexity. Scientist has a hunch that Variable A has dependence mainly on two variables namely x%26amp;y. He conducts experiments by changing these vatiables and measuring the value of A for each value of independent variables x%26amp;y. Then these are plotted in the form of graphs. There are several techniques available to arive at the control equation. This is called curve fitting which is one of the methods in the regressive analysis. Once the equation is arrived at we can consider if there are other minor independent variables which can be incorporated to fin tune the equation.
The independent variable is the one that is changed by the scientist and the dependent variable changes in response to the change the scientist makes to the independent variable. And some experiments also have controlled variables. Controlled variables are quantities that a scientist wants to remain constant, and he must observe them as carefully as the dependent variables