4 ms·

And Florida did not have a major hurricane this year, so it will likely be worse next year.

by coldcode 3y ago

davedx 3y ago
I don't think that's how it works? (Probability)
- blackbear_ 3y ago
  https://en.m.wikipedia.org/wiki/Regression_toward_the_mean https://en.m.wikipedia.org/wiki/Regression_toward_the_mean
- greiskul 3y ago
  There is regression toward the mean, so if Florida had an unusually good year, we would expect that next year to be worse then this year.
  - stavros 3y ago
    Yes but that doesn't really mean much. We always expect it to have, say, 4 hurricanes, so if it had 3, we still expect the same number as always (4). The fact that we didn't have one this year doesn't change next year's expectation.
    - sokoloff 3y ago
      Nor does it change the fact that next year's [unchanged] expectation is worse than this year's observation.
- iamthepieman 3y ago
  Doesn't have to have anything to do with probability. If fewer resources are spent repairing and re-building and the last hurricane event is out of people's minds then I would expect there to be more building resulting in more damage next time a hurricane comes around.
- adhesive_wombat 3y ago
  That is how it works: it's regression to the mean. If you expect a major hurricane every n years and you didn't have one this year, the expected likelihood of one next year (1/n) is greater than what you actually got this year (0). If the non-hurricane damage is independent, then you expect $(1/n * cost of major hurricane) additional costs next year. In a major hurricane year, you expect (1-n)/n fewer such hurricanes next year. And therefore you expect less expensive damage. One could debate whether "likely to be worse" is correct. If there's a a major hurricane every 10 years, there's only a 10% chance of it happening next year. The expected value of the damage is higher, but it's still "unlikely" (as in, less than 50%) to happen at all. So it's expected to be worse, but unless there's over 50% chance of a major hurricane per year, it's not likely to be worse. If year-to-year hurricanes are also independent, then knowing that there was or was not a hurricane this year, it's also no more or less likely that a major hurricane occurs next year then it was looking forward to this year, as of this time last year. But, I don't know if that is an independent thing.
  - lotsofpulp 3y ago
    > That is how it works: it's regression to the mean. If you expect a major hurricane every n years and you didn't have one this year, the expected likelihood of one next year (1/n) is greater than what you actually got this year (0). Not if hurricanes are independently and identically distributed. Which I think you acknowledge could be the case in your last paragraph, but I have not ever come across anything linking hurricane to one another. https://en.wikipedia.org/wiki/Gambler%27s_fallacy https://en.wikipedia.org/wiki/Gambler%27s_fallacy
    - adhesive_wombat 3y ago
      No, it's not a gambler's fallacy. You know you got zero this year, it already happened. You know it's expected 1/n next year (assuming independence, etc), just like every year. So the expected amount of hurricanes next year is more than what you did get this year, which was 0. In total you now (as of now, year 1 end) expect only 0 + 1/n total hurricanes over the two years (this year and next). That is 1/2n per year: less that you would have predicted at the start of this year, which would have been 2/n over two years for 1/n per year. A gambler's fallacy is thinking getting 0 this year means it's more likely than 1/n next year to act to retroactively "correct" 0 this year.
- deleted 3y ago
  [deleted]
- datadrivenangel 3y ago
  People will spend less to protect their property.
- deleted 3y ago
  [deleted]
- paxys 3y ago
  There are different ways of looking at it. 1. Each hurricane is an independent event. Florida expects 5 hurricanes per year on average. There were 0 hurricanes this year, so by definition we can expect more hurricanes next year (because 5 > 0). However, the fact that there were zero hurricanes this year doesn't influence next year's season in any way. The statement is just trivially true. 2. Hurricanes are not independent of each other, but rather get stronger the longer you go without one. So if there were none this year then you will likely bear the brunt of it next season. I know this is a thing for earthquakes and other tectonic activity, but not sure if hurricanes work the same way.
- Vegenoid 3y ago
  I think the confusion here is that you are interpreting the statement as 'since Florida didn't have a major hurricane this year, the chance that they have a major hurricane next year is higher than normal'. This would be inaccurate. What is meant is that since Florida didn't have a major hurricane this year, then next year is likely to be worse than this year, since Florida has a significant chance of being hit by a major hurricane each year.

And Florida did not have a major hurricane this year, so it will likely be worse next year.

davedx 3y ago

I don't think that's how it works? (Probability)

blackbear_ 3y ago
https://en.m.wikipedia.org/wiki/Regression_toward_the_mean https://en.m.wikipedia.org/wiki/Regression_toward_the_mean
greiskul 3y ago
There is regression toward the mean, so if Florida had an unusually good year, we would expect that next year to be worse then this year.
- stavros 3y ago
  Yes but that doesn't really mean much. We always expect it to have, say, 4 hurricanes, so if it had 3, we still expect the same number as always (4). The fact that we didn't have one this year doesn't change next year's expectation.
  - sokoloff 3y ago
    Nor does it change the fact that next year's [unchanged] expectation is worse than this year's observation.
iamthepieman 3y ago
Doesn't have to have anything to do with probability. If fewer resources are spent repairing and re-building and the last hurricane event is out of people's minds then I would expect there to be more building resulting in more damage next time a hurricane comes around.
adhesive_wombat 3y ago
That is how it works: it's regression to the mean. If you expect a major hurricane every n years and you didn't have one this year, the expected likelihood of one next year (1/n) is greater than what you actually got this year (0). If the non-hurricane damage is independent, then you expect $(1/n * cost of major hurricane) additional costs next year. In a major hurricane year, you expect (1-n)/n fewer such hurricanes next year. And therefore you expect less expensive damage. One could debate whether "likely to be worse" is correct. If there's a a major hurricane every 10 years, there's only a 10% chance of it happening next year. The expected value of the damage is higher, but it's still "unlikely" (as in, less than 50%) to happen at all. So it's expected to be worse, but unless there's over 50% chance of a major hurricane per year, it's not likely to be worse. If year-to-year hurricanes are also independent, then knowing that there was or was not a hurricane this year, it's also no more or less likely that a major hurricane occurs next year then it was looking forward to this year, as of this time last year. But, I don't know if that is an independent thing.
- lotsofpulp 3y ago
  > That is how it works: it's regression to the mean. If you expect a major hurricane every n years and you didn't have one this year, the expected likelihood of one next year (1/n) is greater than what you actually got this year (0). Not if hurricanes are independently and identically distributed. Which I think you acknowledge could be the case in your last paragraph, but I have not ever come across anything linking hurricane to one another. https://en.wikipedia.org/wiki/Gambler%27s_fallacy https://en.wikipedia.org/wiki/Gambler%27s_fallacy
  - adhesive_wombat 3y ago
    No, it's not a gambler's fallacy. You know you got zero this year, it already happened. You know it's expected 1/n next year (assuming independence, etc), just like every year. So the expected amount of hurricanes next year is more than what you did get this year, which was 0. In total you now (as of now, year 1 end) expect only 0 + 1/n total hurricanes over the two years (this year and next). That is 1/2n per year: less that you would have predicted at the start of this year, which would have been 2/n over two years for 1/n per year. A gambler's fallacy is thinking getting 0 this year means it's more likely than 1/n next year to act to retroactively "correct" 0 this year.
deleted 3y ago
[deleted]
datadrivenangel 3y ago
People will spend less to protect their property.
deleted 3y ago
[deleted]
paxys 3y ago
There are different ways of looking at it. 1. Each hurricane is an independent event. Florida expects 5 hurricanes per year on average. There were 0 hurricanes this year, so by definition we can expect more hurricanes next year (because 5 > 0). However, the fact that there were zero hurricanes this year doesn't influence next year's season in any way. The statement is just trivially true. 2. Hurricanes are not independent of each other, but rather get stronger the longer you go without one. So if there were none this year then you will likely bear the brunt of it next season. I know this is a thing for earthquakes and other tectonic activity, but not sure if hurricanes work the same way.
Vegenoid 3y ago
I think the confusion here is that you are interpreting the statement as 'since Florida didn't have a major hurricane this year, the chance that they have a major hurricane next year is higher than normal'. This would be inaccurate. What is meant is that since Florida didn't have a major hurricane this year, then next year is likely to be worse than this year, since Florida has a significant chance of being hit by a major hurricane each year.