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My personal risk assessment strategy is to do something like: if my chance of car accident is 1/450 per year, would I pay one car accident in order to get 450 years of driving? If yes, then I drive. I do this for nearly all my risk assessments and I'm wondering how common it is.

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That's not how it works. If the chance of accident is 1/450 per year, your chance of going n years without an accident is (449/450)^n For 100 years it's about 80%.

Aella

@Aella_Girl

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@lumiferrous

I'm not that schooled on probability, but I'm imagining a bunch of red dots, thousands of them. Randomly speckled in at an average of 1 every 450, there is a blue dot. What is the chance that, for any given red dot, there's at least 449 red dots between the blues on either side?

6:36 AM · Mar 5, 2020

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and

wouldn't it be 50%? Tho ofc this isn't the same as "for every red dot I pick, what is the chance I hit a blue dot if I move x spaces down the line", which is what you're talking about?

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and

But anyway that's not really the point of this; I don't know much about probability but I know it's real fucky and unintuitive; my thought experiment is just to help me personally hit judgment calls and have a consistent way of evaluating risk across decisions.

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With a sequence it's easier. Do coin tosses: the chance of one head is 0.5. The chance of two consecutive heads is (head AND head) = (0.5 * 0 5) = 0.5^2 = 0.25. For three consecutive heads it's 0.5^3 = 0.125, etc. Same thing with chances of having n years without an accident.

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But I don't need consecutive years.

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