# probability

bobbob1056th
Posers and Puzzles 15 May '05 08:16
1. 15 May '05 08:16
i know there are many extremely unique things like this that happen all the time, but i still think its rather interesting (this is a true story):

the other day, my day ran over a bird with his car. the next day a fire truck came to his house (my sister made a large fire in the backyard).

both are very unlikely to happen to an individual, let alone the second event happening the day after the first. i wood guess that around 1/10,000 people who walk the earth and own a car will ever run over a bird with their car. think about it, a bird is fast, it can see, it can fly, and of all places what is a bird doing in the middle of the street? then a fire truck coming to ur house probably happens to 1/10,000 people also. lets say the average person will drive a car for 10,000 days total (not accumalative time, of course, this just means that on any one of those 10,00 days you are driving a car at some point.)

so to get the likelyhood for this event happening to any given person, you'd multiply all those numbers (1/10,000^3) which wood give you 10^-12 (1 of one trillion!) however this is nothing compared to the infinite possibilities in life.

anybody disagree with estimates? or have any other extremely unlikely things that have happened?
2. ark13
Enola Straight
15 May '05 14:53
Originally posted by bobbob1056th
i know there are many extremely unique things like this that happen all the time, but i still think its rather interesting (this is a true story):

the other day, my day ran over a bird with his car. the next day a fire truck came to his house (my sister made a large fire in the backyard).

both are very unlikely to happen to an individual, let alo ...[text shortened]... nybody disagree with estimates? or have any other extremely unlikely things that have happened?
Well, first off, I think your estimates are a bit off. I know someone who's hit a bird with their car, and fires happen all of the time. I'm sure those are a bit low.

But regardless, there is something somewhat flawed about you reasoning. Yes, the probability of hitting a bird, then having a fire truck come to your house, is giggle-piggly*10^-grasshopper. But the probability of two slightly strange events occuring on consecutive days is not unlikely at all. There are so many events that people would consider strange, that some unlikely event is actually quite likely to happen. People don't notice all of the strange events that don't happen, only the ones that do. So you didn't say, my dad didn't get abducted by aliens, and my sister didn't start a cult, or etc. And there are millions upon millions of these types of events.

Ok, now addressing the consecutive days issue. Wouldn't you have also surprised if both of those events occured on the same day? Or the same day next week, or the same day next year? There are many times that those two events could've occured that you'd consider strange. And, as I said before, if you're not specifying which strange events before hand, it's quite likely that something strange will happen. So, I'm not at all surprised to hear of these events.
3. 15 May '05 19:531 edit
"Ok, now addressing the consecutive days issue. Wouldn't you have also surprised if both of those events occured on the same day? Or the same day next week, or the same day next year? There are many times that those two events could've occured that you'd consider strange. And, as I said before, if you're not specifying which strange events before hand, it's quite likely that something strange will happen. So, I'm not at all surprised to hear of these events."

You are quite right, although I have considered this.

"There are so many events that people would consider strange, that some unlikely event is actually quite likely to happen." "

This is one of the things that I meant when I said it is nothing compared to the infinite possiblities in life. Good point, thanks for clarifying it.

"People don't notice all of the strange events that don't happen, only the ones that do. So you didn't say, my dad didn't get abducted by aliens, and my sister didn't start a cult, or etc. And there are millions upon millions of these types of events"

I'm not sure what you are getting at, will you please explain?

Also, I'd be interested to know what you think are reasonable chances for those two events to occur.

One more thing. You could easily give events which are impossible, or a very specific single event which is extremely unlikely (the more specific, the more unlikely) so an event which is specific doesn't count.
4. ark13
Enola Straight
15 May '05 21:16
Originally posted by bobbob1056th
"Ok, now addressing the consecutive days issue. Wouldn't you have also surprised if both of those events occured on the same day? Or the same day next week, or the same day next year? There are many times that those two events could've occured that you'd consider strange. And, as I said before, if you're not specifying which strange events before h ...[text shortened]... ly unlikely (the more specific, the more unlikely) so an event which is specific doesn't count.
I have no way of guessing a good probability for those events, but I will clear up the part that you didn't understand.

What I meant was, people don't notice all of the things that don't happen. If no strange event occurs in some given day, no one goes home and thinks to themselves, "Nothing strange happened to me today." And in the same way, no one ever notices all of the strange events that don't happen. What I'm getting at is that when someone says 'that's really improbible!' they mean that those specific events happening together are really improbible. But not that it's really improbible to have two strange things happen to you.

BTW, I know this doesn't make any sense. I couldn't find a way to explain it well.
5. PBE6
Bananarama
16 May '05 14:101 edit
It depends on how you define "events", and how many events happen everyday. For instance, the chance of me winning the Lotto 6/49 is 1 in 14 million, which is why I never win. But if I purchased 1 billion random tickets, I would expect to win (losing all the Queen's money in the process). The more attempts there are, the more likely improbable events will happen.
6. Palynka
Upward Spiral
16 May '05 14:37
All events are unique in the real world and it makes no sense in calculating what were the odds after they occur.

It's like going out, looking at the first car plate number you see and saying "Wow! What were the odds of the first car that I saw today having exacly that license plate number?"
7. 16 May '05 15:271 edit
Originally posted by bobbob1056th
i know there are many extremely unique things like this that happen all the time, but i still think its rather interesting (this is a true story):

the other day, my day ran over a bird with his car. the next day a fire truck came t ...[text shortened]... ? or have any other extremely unlikely things that have happened?
What basis do you have for any of your 'analysis'? You are just pulling completely arbitrary numbers out of the air.

See Palynka's post above for some perspective.
8. 16 May '05 20:501 edit
Originally posted by Palynka
All events are unique in the real world and it makes no sense in calculating what were the odds after they occur.

It's like going out, looking at the first car plate number you see and saying "Wow! What were the odds of the first car that I saw today having exacly that license plate number?"
that's correct, and that's why I said the events can't be too specific!
9. 16 May '05 20:531 edit
Originally posted by davegage
What basis do you have for any of your 'analysis'? You are just pulling completely arbitrary numbers out of the air.

See Palynka's post above for some perspective.
my analysis is using my brain to find what I think are reasonable estimate (and then doing the multiplication ðŸ˜‰)

one thing that's easy to think of that is very unlikely is that you win the lottery and you win a different lottery the next day (or same day, it really doesn't matter when)