Can someone please give me a definition and example for independent, dependent variables and control group?

I need to find them in a statement and I have no idea what the books definitions are saying and the examples are crap.|||I agree totally with you that the examples given on the web are a load of crap:).





Now let us make it as simple as possible. Say you and a friend are going on a diet (you and fran). You both have to reach a target of say a drop of 10 kilos, and the third friend (mary) is also going on the same diet and has the same weight as you both.





Now let us say that Mary is the control group. i.e. she follows the diet regime to the exact method as given in the diet, she eats only fruits and vegetables and she takes no cokes, but she has a controlled amount of Yogurt no sweets, no snacks in between, she religiously eats only fruits and vegetables and she can eat as much as she wants whenever she wants, as given in the diet. The diet says that if Mary follows this diet she will lose 10 kilos in a month. She has no interest in the gym and is not a sporty type.





You and fran also go on the diet. You are a meat eater and the thought of not eating meat for one month nauseates you. So you decide to become the dependent variable by eating one meal of meat each day while going the routine with the rest of the diet and you will have a controlled amount of yogurt as well, the same amount Mary is allowed. And you agree that you will not go to the gym because Mary does not want you to go to the gym. Mary is trying to prove that her vegie diet as given "like a religion" works!





Fran likes yogurt and she takes the same quantity of yogurt that you and Mary take. Fran occasionally likes the sweets, but she does not tell you about it and she will ocasionally snack on the same quantity of meat that you do, but she eats her sweets so she becomes the independent variable because her result and she may take coke as well, and sometimes pig out on chicken. She becomes the independent variable because she is constantly changing her diet. She also feels super guilty so she throws in an occasional visit to the gym.





At the end of the month, your findings would prove whether the diet shoudl be followed religiously the way Mary did it, or whether it can be changed slightly, the way you did it, or whether your friend Fran has come out the winner because she also threw in a session at the gym. You all would thus prove that you could vary the diet and still lose 10 kilos by other measures which would make the diet certainly more interesting to the average user.





Now the scientific method of calculating this would be the question on whether taking Calcium would increase your age by about 5 years.


Three groups of people are used


1 group is given Calciumin varying quantities from say 10 mg to 50 mg daily. (independent variable)


the second group is not given calcium and given a medicine that they think is calcium but could be chalk but it is 10mg to 50 mg daily.(dependent variable)


The third group is the control group who given a certain dosage of calcium would have to prove that there is a significant increase in their life span say 10 mg daily.


The scientists would then find out after a period of 5 years, whether some of their patients in the first group have dropped dead which proves that even if you give them 10mg to 50mg a day, they die in any case.


The second group may also drop dead or they could live longer than the 1st and 3rd groups because they feel that the calcium has given them longevity and they were told that this was a test to increase their longevity so they believe and that generates its own Karma.


The control group is the most rigid and inflexible and will be monitored so that they cannot do anything that is outside what is required for the scientists research but they could also die for other reasons while undergoing the test for calcium.


So much for research:).. You can have several controls to get the best results by giving 6 of your friends the same diet and you would have each of them change only one item in the diet to include the person's likes :-


John takes chicken but follows the rest of the diet diligently


Jennifer takes Sugared drinks and follows ....


Pauline takes Coke


Patricia eats cake


All these must be measured quantities and cannot be left to the whim of the eater:)..|||An independent variable is something that you control. The dependent variable is the effect of your experiment. The control group is a group which you observe, but don't interfere. You compare it to the group to which you interceded.





For example, I want to know whether adding fertilizer will effect the growth rate of flowers. I add 1 tablespoon of fertilizer to a 5 flower pots once a month. Let's call this the experimental group. The amount of fertilizer I add is the independent variable, because I control how much fertilizer I add.





I measure the growth of the experimental flowers. The amount of growth is the dependent variable, because it is the effect of the amount of fertilizer I add.





I have a second group of 5 flowers. It gets the same amount of sun and water as my experimental flowers, but I don't add any fertilizer to these flowers. These flowers are my control group. I measure how much this second group of flower grows and compare it to the experimental group.