Experiments are studies involving intervention by the researcher beyond that required for measurement. The usual intervention is to manipulate some variable in a setting and observe how it affects the subjects being studied (e.g., people or physical entities). The researcher manipulates the independent or explanatory variable and then observes whether the hypothesized dependent variable is affected by the intervention. 

Discuss what essential characteristics distinguish a true experiment from other research designs.

Evaluate what ethical problems you see in conducting experiments with humans. Experiments are studies involving intervention by the researcher beyond that required for measurement. The usual intervention is to manipulate some variable in a setting and observe how it affects the subjects being studied (e.g., people or physical entities). The researcher manipulates the independent or explanatory variable and then observes whether the hypothesized dependent variable is affected by the intervention.  What essential characteristics distinguish a true experiment from other research designs? What ethical problems do you see in conducting experiments with humans?