Yesterday (April 7th, 2018), my Grandmother from my Mom's side passed away. Later on that same day, less than 24 hours apart, my other Grandmother (Dad's Mom), passed away. My question is simple; what are the odds of this happening? I searched around but haven't found anything close to this.

  • $\begingroup$ Sorry for your loss - my condolences. All days being equally likely, and assuming independence, there are $365^2$ possibilities for choosing two days, but only $365$ for choosing a common day. The chances of this happening are ${365 \over 365^2} = {1 \over 365}$, therefore. $\endgroup$ – Ami Tavory Apr 8 '18 at 12:56
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    $\begingroup$ It all depends on the reference population: both grandmothers, all grandparents, all relatives, ... $\endgroup$ – Xi'an Apr 8 '18 at 13:13
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    $\begingroup$ Ami Tavory seems to be assuming both grandparents die in the same year. There is no clear answer t this problem. $\endgroup$ – Michael R. Chernick Apr 8 '18 at 14:03
  • $\begingroup$ See stats.meta.stackexchange.com/a/3207/17230. $\endgroup$ – Scortchi - Reinstate Monica Apr 8 '18 at 19:04

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