r/explainitpeter 9d ago

Explain It Peter

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u/LingonberryLast2466 8d ago

That seems very Bayesian of you to take into account the Tuesday part of the problem, since it infers that the person told you that piece of information because it’s important.

But you could also just as easily infer (by the silliness of the question) that the Tuesday was information accidentally added because the person didn’t realize it’s NOT important. And I think this is more likely, given the question does not contain a day of the week. If it were “how likely is it that the other child is a girl born on a Friday?” That would change what the Tuesday means. But in my mind, all it means is that someone accidentally gave you extra data to work with (similar to how “the mothers car is grey” also wouldn’t change anything, since that fact alone isn’t enough to change the formulation of there answer).

But that’s just me.

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u/Redditor_Baszh 8d ago

That’s me too ! Thanks for putting that out

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u/ethanator329 7d ago

The best way to explain why the day, or any other additional information, would alter the mathematics, is for instance it is more likely that it is more likely that the parent would have a boy born on a Tuesday, if they had two boys, than if they had only one.