9 ms·
A 1 in 36 million chance for three breaks in one day. https://mathb.in/80217 https://mathb.in/80217
by ValentinA23 2y ago
A 1 in 36 million chance for three breaks in one day.
https://mathb.in/80217 https://mathb.in/80217
- gleenn 2y agoThat's assuming independence. I'm not ruling out sabotage but the world is often not fully independent. A storm or an anchor both may affect multiple cables if they're in generally the same area which would definitely make the probability far more likely than those stated. (edit typo)
- ValentinA23 2y agoIndeed ! https://www.datacenterdynamics.com/en/news/lithuania-sweden-subsea-cable-cut-was-10m-from-severed-finnish-german-cable/ https://www.datacenterdynamics.com/en/news/lithuania-sweden-... >Lithuania-Sweden subsea cable cut, was 10m from severed Finnish-German cable
- lrasinen 2y agoI don't buy that number (no source is attributed to it), or rather, I don't believe there's a single incident causing this. The C-Lion1 cable is predominantly North-East - South-West whereas the BCS cable is NW-SE. They do meet, but the C-Lion1 operator Cinia says their cable broke about 700 km from Helsinki, east of the southern tip of the Öland island. That's easily over 150 km south from where the cables meet. Also, C-Lion1 was reported broken at 4m, and the BCS cable at 10am the previous day.
- froh 2y agothe contrast with independent random events is exactly the point of the comment you've replied to, isn't it?
- jeltz 2y agoThe grandparent comment is total nonsense which sounds smart but is not. Damages from accidents are not independently random either. Or do you think it is virtually impossible that 140 people die on the same airliner? It is likely the same ship cut both either by accident or intentionally. I am leaning towards sabotage but that two cables were cut means very little.
- sach1 2y agoWhat are the odds 140 people would all die from an airplane crash on the same day? Wild /s
- amelius 2y agoThe point is that even without a malicious actor the odds are way lower than you'd think.
- UltraSane 2y agoI was told in my stats class that events in the real world are almost never truly independent.
- defrost 2y agoI'm supporting gleenn who beat me by seconds to much the same observation. Clusters are a thing.
- threeseed 2y agoAnd what about adding in the chances of a Russian spy ship seen relatively near by only a few days earlier: https://www.theguardian.com/world/2024/nov/16/russian-spy-ship-escorted-away-from-internet-cables-in-irish-sea https://www.theguardian.com/world/2024/nov/16/russian-spy-sh...
- arandomusername 2y agoIrish sea is relatively near to the Baltic sea?
- threeseed 2y agoAccording to Google it's 854nm. The spy ship is alleged to be able to go 15 knots which means it could make the distance in 2.5 days. https://ukdefencejournal.org.uk/russian-spy-ship-present-off-british-coast/ https://ukdefencejournal.org.uk/russian-spy-ship-present-off...
- CrazyCatDog 2y ago“Knowing that 200 undersea cables break every year globally, estimate the probability that 3 cables break in the baltic sea on the same day.” I’m stealing this to use for grad-student mock-interviews—thank you!
- deleted 2y ago[deleted]
- Moru 2y agoHint: The cables are often very close. If one breaks, the otherone also breaks :-)
- gitaarik 2y agoWhy would cables close to each other break?
- leovingi 2y agobecause if it's an accident and someone is dragging an anchor behind them, if the cables are only meters apart then they are going to cut both
- 0points 2y ago[flagged]
- jeltz 2y agoNo, because anchors can easily damage several cables close to each other. And that is how it almost certainly happened no matter if it was an accident or sabotage.
- onionisafruit 2y agoToday’s that day. Start the clock for the next one.
- kqr 2y agoWhy is this analysis focused on the Baltics? That's p hacking, given that it happened to happen in the baltics. Let's instead say there are roughly 20 ocean regions we would post hoc consider "the same". Now, given a breakage, what is the probability of at least two more in the same region and day? This is a Poisson distribution with lambda=200/365/20. The probability of two more independent breakages is 0.04 % for that specific day. But again, picking a specific day would be p-hacking. Zooming out, an event that rare is expected to happen every seven years or so. Now, "every seven years" is a far cry from "1 in 36 million." Whenever you get crazy p values like that, there is often an error or overlooked assumption in the analysis. ---- If you like this sort of thing, have a stab at forecasting competitions! I can recommend the Metaculus Quarterly Cup. The current one is in full swing so use the remaining 1.5 months of the year to practice and then you're set for when the January edition starts.
- ValentinA23 2y agoI see, this was in fact what I had in mind. The maths I posted represent the horizon of my knowledge in probability and was surprised how well o1-preview was able to output correct numerical calculations. Having said that how would the odds look like if we factor in the fact the Baltic Sea is one of two zones with the most geopolitical tensions (along with Taiwan). --- Thanks for the Metaculus recommendation. I was a bit disappointed in the lack of maths in the comments in general. Can you recommend something in the vein of Leetcode with various degrees of difficulty, from very basic to advanced problems ? I'm both interested in probability and statistics
- kqr 2y agoSomething in thr vein of leetcode would be really useful to train people in forecasting, but given how subjective it is maybe difficult to pull off.
- red_admiral 2y agoOne a day is happenstance. Twice is coincidence. Three times is enemy action.
- ikiris 2y agoOr they’re right next to each other and the laws of physics continued to exist for the object that struck them.
- gosub100 2y agoYou can't even assume they follow a normal distribution. For all we know, ships drop anchor more on certain days or weather conditions. That's just the start of the rabbit hole.