The one where it's Elvis' birthday
Happy Birthday, Elvis!
Yeah Wally, Andrea, Kimberly, you know who, I missed your birthdays but caught his. (Though Andrea, I did try to call a couple of times but couldn't get through...) Deal.
Oh, and Happy New Year! To everybody.
I think I need to blog more, because otherwise there's too much in each entry. Or maybe I should just say less.
I'm obviously still behind on New Zealand, but I've just loaded entries (Sydney, Katoomba, Canberra) from my first 10 days in Australia. Maybe too much detail, maybe not enough, but let me know. And don't worry, I won't always give you details of every place I go. But anyway,
sg
3 comments:
Hi Seth, what is the probability of 3 brothers each having 1 daughter and 1 son?
And who do the Steelers play in the playoffs this week?
Dr STSK,
We need to assume that:
- each brother has 2 children
- the probability of each child being a daughter (or a son) is independently 50%
- the order (daughter, then son) doesn't matter
If these are all true, then for each brother the probability of having 1 daughter and 1 son is 50%. (You could have SD, DS, SS, DD, each of which is equally likely and half of which give you 1 and 1). So for the 3 brothers to each have 1 and 1, the probability is 1/2 * 1/2 * 1/2, or 1/8.
If birth order is taken into account, that is "1 daughter and 1 son" is different than "1 son and 1 daughter", then it's 1/4 * 1/4 * 1/4, or 1/64, much less likely.
Now, keep in mind that you'd have maybe asked the same question under different circumstances. Say there was a kid named "Larissa", who followed a kid named "Lucy". Your question might have ended with "having 2 daughters?"
So in one sense, your question can be understood as the probability that 2 brothers have the same mix as some third brother. So here, we're really only working with 1/4 * 1/4 = 1/16.
While that may seem unlikely, keep in mind that there are many more than 16 (or even 64!) sets of 3 brothers, each of whom has 2 children. So while it may seem unlikely that these 3 brothers have the same, it's extraordinarily likely that there somewhere exists a set of 3 brothers each having 1 daughter and 1 son.
Now, that said, who will be the #2 pick in the upcoming draft?
-Dr SG
I didn't get your call from NZ, but I was very envious when Brita, who was standing right there, told me she'd just gotten a message from SG! Well, I guess my phone doesn't get calls from afar... Hope you have a nice birthday too!
Hey, any interest in going to Japan this summer?
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