What is unusual?

In a medical study, many observations are made in an effort to obtain a data sample representative of a population. In this activity, you’ll see how standardized scores and the Empirical Rule can be used to determine if an observation is usual or unusual.

Around the world, pharmaceutical companies conduct clinical trials to evaluate the safety and efficacy of their drugs. Clinical trials are research studies performed on people and are aimed at evaluating whether a new drug is safe and effective. People who participate in clinical trials are volunteers.

Mice are often used for evaluation before testing chemicals and pharmaceuticals on humans in medical studies. One reason for this is that scientists know a lot about the genome of a mouse. They are bred in labs to be identical, so the only thing different between them is the treatment. Mice also have short lifespans, which allows scientists to model the effects of a drug over their entire lifespan (about [latex]800[/latex] days). It is much more difficult to understand the effects of a drug over the lifetime of a human.

Consider a study concerned with learning how a drug or a treatment affects the body. The toxicity of a chemical and its impact on vital organs are of interest when assessing the effects of a chemical treatment. A standard method used to measure the level of toxicity in an organ is to use the organ’s weight.^[1]