Final answer:
In an experimental design, it is imperative to demonstrate the influence of the independent variable on the dependent variable by manipulating one while measuring the other, using a control group, and controlling for lurking variables to ensure that outcomes are due to the experimental treatment.
Step-by-step explanation:
In any experimental design, it is crucial to demonstrate the influence of the independent variable on the dependent variable. The independent variable is what the researcher manipulates to observe the effects on the dependent variable, which is the aspect of the experiment that is measured or observed. To ensure that any observed effects are actually due to the independent variable, various controls are employed. These include the use of a control group, which does not receive the experimental manipulation, random assignment of subjects to different groups to eliminate bias, and sometimes blinding of participants and researchers to the conditions to prevent expectancy effects.
To ensure that the difference in outcomes between groups is due to the experimental manipulation, all other potential variables, known as lurking variables, must be controlled. This is achieved through careful experimental design, which includes clear definition of the explanatory and response variables, the population being studied, and the treatments used. Blinding and the use of placebos help to maintain the integrity of the experiment by protecting against bias.