Manipulated variable or also called the controlled variables are variables in which you regulate. Manipulate or as said control. By this you want to certain the outcome of a certain experiment. Making it close to which you want it or desired it to be, possibly. Characteristics could be:
1. You are able to have govern or a certain variable is controllable.
2. The outcome or effect of a particular variable was what you were determining or were testing with high probability
3. You can either increase or decrease the level of which the variable could take effect on a dependent variable.