The information seems to be explained adequately. However, you need to think of something the concerns YOU that may effect behavior. Effect of any specific drug on some condition? The different responses to oral instructions as compared to written instructions? Different values of extra credit assignments on whether these values effect the use of this option?
Hint: Be sure to indicate how you might control extraneous variables (variables other than the independent one that potentially can affect the dependent variable, so they must be controlled.) If possible, you try to keep them constant between the experimental and control group.
As an example, suppose you want to find out if fluorides reduce dental cavities. You would find two groups, trying to control the extraneous variables. Extraneous variables are found by surveying previous research in the area. In this case, you would match the groups in terms of previous history of cavities, diet and dental hygiene habits including how and how often they brush their teeth.
The experimental group would get toothpaste with the independent variable, the fluoride, while the control group would not have the fluoride in their toothpaste. The toothpaste without the fluoride would be the placebo.
The dependent variable would be the number of cavities after participating in the experiment for a time. The dependent variable indicates the results, but it is not the results. At the end of the experiment, both groups could have no change in cavities or one of the groups could have a greater reduction in cavities. (Of course, if the fluoride increased cavities, you wouldn't want to use it.) All of these varied results would be indicated in terms of the dependent variable.
If only the subjects do not know who is getting the fluoride, it is a single blind experiment. If both the subjects and experimenter do not know, it is a double blind experiment.
I hope this helps. Do not use this example.