The Primary Difference Between an Experimental (Randomized) Clinical Trial and Other

question 1302

Multiple Choice

The primary difference between an experimental (randomized) clinical trial and other observational study designs in epidemiology is that in an experimental trial, the

• A) study is prospective.
• B) investigator determines who is and who is not exposed.
• C) study is case controlled.
• D) study and control maps are selected on the basis of exposure to the suspected causal factor.

Learn about water conservation techniques in agriculture.

Understand the consequences of excessive groundwater withdrawal and management strategies for water scarcity.

Understand the different scales used to measure earthquakes.

Identify secondary effects of earthquakes.

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Definitions:

Pain-Controlling Chemicals

Biological substances produced by the body, such as endorphins, that help to naturally relieve pain.

Neurons

Special cells found in the nervous system that are designed to transfer information to other nerve cells, muscles, or glandular cells.

Inhibitory Neurotransmitter

Chemical substances released by neurons in the brain to decrease the activity of other neurons, thus reducing excitability and preventing overstimulation.

GABA

A major inhibitory neurotransmitter in the brain involved in reducing neuronal excitability throughout the nervous system.