>Hello
>
>Can anyone suggest the best way to calculate the probability
>of losing two close relatives (Father/Maternal
>Grandmother)in separate (natural) events and different
>geographic locations on the same day? I have one brother who
>presumably shares the same probability.

Sure. First by natural, I'll assume you mean natural causes. If you mean earthquakes, floods and the like, and they don't both live in a hurricane or brushfire prone area, that would result in a significantly lower chance than I'll give here.

You didn't mention ages, but I'll assume the father is 45-64 and the grandmother is 65 or older. I'll only include the top ten causes of death because that's all that http://www.disastercenter.com/cdc/ lists.

Now, the grandmother has to die sometime, the only question is what is the chance that the father dies the same day. Data for 65 and up deaths indicate about a 98% chance that death is by natural causes and is not an accident.

The chance the father dies that day will be about (1/365)(663.2/100000) or about .0018%. So (.0018%)(98%) is about the chance that this unfortunate event occurs, about 18 in a million. Given a country with 300 million people, it's going to happen to about 5400 of them on average.