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Random sampling intuition

Created by Brit Cruise.

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Video transcript

Voiceover:I have a little simulation here that saves us time. It does the random picking for us. Voiceover:Mm-hmm. Voiceover:And it allows me to start with four whites and two blacks, and I'm going to have the computer do many selections for us. Voiceover:So, this is every selection the computer's doing, the equivalent of randomly picking out a marble. It's shaking it and randomly picking it, and you see that now the percentage of white, it's getting pretty close to the actual percentage, or a 4:2 ratio, I should say, of white to black. Voiceover:So, I think I believe you now, because at the beginning, I see a lot of variation- Voiceover:Right. Voiceover:On this graph over time, and now it's kind of flat-lining. Voiceover:It's definitely, it feels like it's converging to the actual proportion, and once again, there's some chance that it didn't. We could have, it could have been just one of those one in a quadrillion circumstances (laughs) where you just kept picking a white every time, but this is consistent with the intuition, as the more trials you have, it just becomes harder and harder, the probability of it being a significant departure from the actual proportion becomes lower.