What is the manipulated variable?

What is the difference between a manipulated variable and a responding variable in a controlled experiment?

• Answer:

  A variable is something which can change, that is have different values. The proper scientific terms for these are: Dependent and Independent variable. The independent variable is the thing that you vary during an experiment. The dependent variable is what changes as a result of that manipulation. A manipulated variable is the variable which you deliberately alter the value of. So, you will know the values of this variable before you do the experiment. This variable is also called the independent variable. A responding variable is the variable which you have to measure to get your results. So, you do not know the values of this variable until you measure it. This is also called the dependent variable. For example, to find out if your heart rate depends on exercise, you could do different amounts of exercise (the manipulated variable) and measure the heart rate (the responding variable). The above answer is well written, so I will just add a couple of examples. The standard linear equation is defined as 'y = mx + b'. y = 4x + 10, for example, could be charted on a Cartesian coordinates graph as a straight line that has a slope of 4 and a y-intercept of 10. In such linear equations, x would be described as the manipulated, or independent variable, while y would be the responding, or dependent variable. In another example suppose you are traveling in a car at 50 miles per hour. How far would you go if you traveled three hours? In this example, x would be the number of hours traveled, and y would be the total distance traveled in miles. The equation would be y = 50x. In this equation, x is the independent variable, and y is the dependent variable. By substituting 3 for x (because the question asked how far would you go in three hours), we can calculate that you would travel 150 miles. So the distance you travel (y) depends upon how long you traveled (x).