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.
1 Pain-relieving medications. Also known as acute or abortive treatment, these types of drugs are taken during migraine attacks and are designed to stop symptoms.  Preventive medications. These types of drugs are taken regularly, often on a daily basis, to reduce the severity or frequency of migraines.