You must analyze all parts of a given scenario (example).
If you know the definitions for the independent variable, dependent variable, control and experimental group in a problem than it would be less complicated to figure out what they are in any given example. So, here are the definitions:
Independent variable: the factor that you change
Dependent variable: the factor that is measured
Control group: the factor that is kept the same
Experimental group: the group in an experiment that receives the variable being tested
Furthermore, here is an example:
One chicken is injected with a growth hormone while another chicken is not injected. Both chicken are weighted after a year.
Independent variable: Chicken that was injected (the reason for this is that in this experiment
Dependent variable: Weight of chickens (the reason for this is that the weight of the chickens is what is being measured and the weight of a chicken depends on whether it was injected or not).
Control group: Chicken that wasn't injected (the reason fro this is that nothing was done to the chicken; it stayed the same).
Experimental group: Chickens that were injected (the reason for this is that this was the group in which the growth hormones were tested on).
For extra practice here are some other examples and their answers (try them out by using the definitions before looking at their answers).
- A bug repellent is sprayed on one arm while the other arm isn't. The number of bug bites is recorded after two hours.
- Javier sleeps nine hours before the night of his science exam. His twin sister has the same exam tomorrow and sleeps six hours the night before the test. Afterwards, they compare their scores.
Dependent variable: Number of bug bites
Independent variable: Sprayed arm
Control group: Arm not sprayed.
Experimental group: Sprayed arm
Dependent variable: Their scores
Independent variable: Twin sleeping six hours
Control group: Javier sleeping 9 hours
Experimental group: Twin sleeping six hours