While we looked at sampling in the previous section, experimentation is completely different. Although they seem similar, sampling is merely observation of individuals and variables, while experimentation goes a step further by imposing a treatment on the subject and then observing the response. The basic tenents of experimental design are as follows:

• Control the effects of the lurking variable/variables (variable not being tested but effects response).
• Randomize the assignment of subjects to treatments in order to prevent bias
• Repeat the project many times and compare results