<P> If Volume is made the control variable and it is not allowed to change throughout the course of the experiment, the relationship between dependent variables, Pressure and Temperature, can quickly be established by changing the value for one or the other . For instance, if the Pressure is raised then the Temperature must increase . </P> <P> If, however, Temperature is made the control variable and it is not allowed to change throughout the course of the experiment, the relationship between the dependent variables, Pressure and Volume, can quickly be established by changing the value for one or the other . For instance, the Pressure is raised then the Volume must decrease . </P>

Is a control group the same as a control variable