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Sampling Methods, a la Shmoop.

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Ten days after setting sail from London with his…questionably hygienic…crew… [Captain Cornelius with his crew on a ship]

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…Captain Cornelius discovered a parchment, reading:

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"On the next full moon, Cornelius sleeps with the fish."

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… Captain Cornelius created a poll to see if the crew was planning a mutiny. [Cornelius designing a poll on a parchment]

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He spent the better part of a month pondering the benefits of random sampling versus stratified sampling.

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In random sampling, the polltakers would be chosen at random… [A roulette wheel spinning]

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…each sample having an equal chance of being chosen.

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However, the Captain Cornelius remembered that 20% of the crew were British royal navy men…

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… while 80% of the crew were pirates. [A UK flag and a Pirate flag on the ship]

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This seemed like some important information about the crew’s subpopulations, or strata.

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In a stratified sampling, 20% of the polltakers would be made up of navy men while

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80% would be pirates.

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By taking samples proportionate to the crew’s subpopulations…

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…the likelihood of accurate information is increased. [Cornelius swimming with sharks]

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Well of course, he could have also used Systematic Sampling…

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…where he might have lined up all 300 crew members and then just polled every tenth guy

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to get a 10% sample. [Crew of men selected in systematic sampling]

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Or he could have used Convenience Sampling, where the captain would have

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simply polled those crew members who were within shouting distance… [Cornelius shouting and crew members appear]

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…so he wouldn’t even have to get out of bed.

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But he knew that stratified sampling would be the best option here...

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…because he knew certain characteristics about the crew that could change

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the results if the poll were conducted in a different way.

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In the end, Captain Cornelius succeeded in collecting conclusive evidence that a mutiny [Cornelius walking the plank on the ship]

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was indeed being planned.

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Maybe he’ll be able to share the results of his poll with Davy Jones. [Cornelius thrown off the plank into the sea]

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