There are various sampling methods. The one chosen will depend on a number of factors (such as time, money etc.). 1. Random Sampling Everyone in the entire target population has an equal chance of being selected. This is similar to the national lottery.
Various types of medications have been evaluated for migraine prophylaxis, including beta blockers, antidepressants, anticonvulsants, nonsteroidal anti-inflammatory drugs (NSAIDs), angiotensin blockade agents, and calcium channel blockers.
Combination or cocktail drugs that contain a combination of caffeine, acetaminophen, and aspirin (or alternatively, caffeine, acetaminophen, and ibuprofen) are often marketed as relief from migraines and tension headaches. Excedrin, one brand name of the type, is a combination of caffeine, acetaminophen, and aspirin.