"For those of you who are interested in statistics, this is a five-sigma event. So it's five standard deviations beyond the mean. Which means that if nothing had changed, we'd expect to see a winter like this about once every 7.5 million years.
[...]
She fears a further change in the balance could trigger a tipping point from where it's difficult to reverse the trajectory. "We might end up in a new state," she said. "That would be quite concerning to the sustainability of human conditions on Earth, I suspect.
Could we (I'm sure it's not just me) - get a ELI5 for standard deviation?
If you throw darts at a bullseye and are good at it, most will hit near thr bullseye and fewer and fewer will hit the farther away you get.
Scientists will often take their models and data and say, "okay how far off were we?" as if the model were the dart board and the data was one or more throws.
Standard deviation is a standardized measure of how far one is from the center of the distribution of "dart throws". For the very common bell curve (Gaussian distribution), it's a particular distance from the mean value.
In practical terms, they're saying they threw a dart and it ended up two blocks away. The model is wrong now - the world doesn't work like it used to and how it waa predicted to work.
Just to be clear, it's not 5 standard deviations off of modeled ice, it's 5 off of previously observed ice. I'm assuming at the cross section where the difference is deepest. Taking the time series from this year in total, it looks more like 3 or 4 sds off the mean
Ah, interesting. Both are bad in their own ways.
deleted by creator
It’s the root mean square about the mean of the number set
Thank you for sharing some of your "I Fucking <3 Math!" stand up routine. We are honored.
just wait til you catch me on eigenvector night
deleted by creator
The whole act is just longer and shorter versions of the same one joke, something about their identity matrix being an attack helicopter? You know, right-multiplication "humour"?
In this context it's about the statistical significance of an event. Here it means that Antarctica not having ice is due to something like climate change, because the occurrence is so outside normal parameters.
See my other comment
Most complex random things follow a normal distribution. These have a mean (average value), and standard deviation (how spread out from the mean it is). If you get some measurement of your random thing, you can tell how likely that was by checking how many standard deviations away from the mean it is.
Within one standard deviation - happens 68% of the time
Within two standard deviations - happens 95% of the time
Within three standard deviations - happens 99.7% of the time
Within four standard deviations - happens 99.993% of the time
Within five standard deviations - happens 99.99994% of the time
Within six standard deviations - happens 99.9999998% of the time
Five standard deviations is the threshold where even particle physicists will say, "Yeah bullshit that happened at random, something else is going on here."
It's a shame the American media makes no effort to explain this stuff and instead they idiotically use vague phrases and adjectives.
[Edit: Of course - they usually entirely ignore stuff like this.]