(Redirected from experiment subject)
- AKA: Study Member/Subject.
- See: Experiment Outcome.
- QUOTE: In the design of experiments, the experimenter is often interested in the effect of some process or intervention (the "treatment") on some objects (the “experimental units"), which may be people, parts of people, groups of people, plants, animals, etc. Design of experiments is thus a discipline that has very broad application across all the natural and social sciences and engineering.
- A unit is a person, animal, plant or thing which is actually studied by a researcher; the basic objects upon which the study or experiment is carried out.
- Failure to identify correctly the experimental unit is a common mistake which can result in incorrect conclusions. The experimental unit is the physical entity which can be assigned, at random, to a treatment. Commonly it is an individual animal. The experimental unit is also the unit of statistical analysis. However, any two experimental units must be capable of receiving different treatments. Thus, if mice in a cage are given a treatment in the diet, the cage of animals rather than the individual animal is the experimental unit as mice in the cage can not have different treatments, and they may be more similar than mice in different cages. This means that the p-values in the statistical analysis may be incorrect if it is assumed that the mouse is the experimental unit. In this case the statistical analysis should normally be done using the mean of all the animals in the cage.
- (Jones & Kenward, 2003) ⇒ Byron Jones, and Michael G Kenward. (2003). “Design and Analysis of Cross over Trials." CRC Press. ISBN:0412606402