Control group, experimental group, dependant and independant variables.?

I am very confused by the definition of these. most confusing is are control groups the same as dependant variables? here is the question in my book:





the difference between the experimental and control groups should be that the:


A- control group receives the independent variable and the experimental group does not.


B- the experimental group receives the dependent variable and the control group does not.


C- nothing, these are synonyms that refer to the same group


D- control group receives the dependent variable and the experimental group does not; the experimental group receives the independent variable and the control group does not.


E- none of the above





whats the right answer? can someone please explain how these are all linked because I don't understand..


thank you|||Control group - a group of "things" that you leave constant, in order to compare your experimental results to them.


Experimental group - another group of "things" that you might change to see the effect your change has.


Independent variable - the measured things YOU change.


Dependent variable - the thing that changes in response to your change to the dependent variable.





This is a ridiculous example, but maybe it will illustrate it for you:





Say you have a normal block of wood, like a short length of pine 2x4. You want to investigate the effect of painting that wood on the buoyancy of it. So what you do is you take a few pieces of 2x4, the same size, and you leave the first one unpainted. You haven't changed anything about it so it remains your control. Then you paint one side of the next one. And two sides of another one, etc. until you have all six sides painted. Then you drop them all in the water and measure how much the top of the wood sticks out of the water.





Control group - unpainted wood


Experimental group - painted wood blocks


Independent variable - amount of paint


Dependent variable - amount the wood sinks.





You could then graph sides painted vs. amount the wood sinks, with the sides painted on the x/horizontal axis and amount of sink on the y/vertical axis.





I hope that makes sense. Hopefully it answers your question.