Antarctic sea ice has usually been able to recover in winter. But this time it's different, with levels taking a sharp downward turn at a time of year when sea ice usually forms reliably — and experts are worried.
For seriously though, its explained in the article:
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.
As was mentioned in another comment, it’s a statistical term that measures the standard deviation. It basically tells you how “far” from the center of the bell curve you are with your data points. The higher the sigma, the less likely it is that an observed event was a fluke.
For example, 1-sigma event has a ~37% chance of being a “coincidence”, and 2-sigma has a chance of about 4.5%.
In science, 3-sigma (0.135%) is the first publishable certainty, it’s when something becomes significant enough to start a discussion.
And 5-sigma is the most common threshold for claiming discovery. 5-sigma events have a 0.0000287% chance of being a coincidence or some random happenstance. Or one in 3.5 million.
Higgs boson discovery was announced after 5-sigma certainty was reached. It means that if that particle didn’t actually exist, the chance of the experiments producing observed results would be 1 in 3.5 mln.
If you read the section on etymology of the business term, it was referring to the metric of quality control. Basically it means your QC is so good that a bad unit gets shipped only a tiny fraction of the time.
Processes that operate with “six sigma quality” over the short term are assumed to produce long-term defect levels below 3.4 defects per million opportunities (DPMO). The 3.4 dpmo is based on a “shift” of ± 1.5 sigma explained by Mikel Harry.
Whats sigma?
Sigma balls. Am I doing this right?
For seriously though, its explained in the article:
As was mentioned in another comment, it’s a statistical term that measures the standard deviation. It basically tells you how “far” from the center of the bell curve you are with your data points. The higher the sigma, the less likely it is that an observed event was a fluke.
For example, 1-sigma event has a ~37% chance of being a “coincidence”, and 2-sigma has a chance of about 4.5%.
In science, 3-sigma (0.135%) is the first publishable certainty, it’s when something becomes significant enough to start a discussion.
And 5-sigma is the most common threshold for claiming discovery. 5-sigma events have a 0.0000287% chance of being a coincidence or some random happenstance. Or one in 3.5 million.
Higgs boson discovery was announced after 5-sigma certainty was reached. It means that if that particle didn’t actually exist, the chance of the experiments producing observed results would be 1 in 3.5 mln.
It’s also used in business. Six sigma is the holy grail of “close to perfection”.
Interesting, haven’t heard about that. Can you give an example of how it’s used in business? What is actually measured?
I couldn’t do better than Wikipedia.
Thanks. So I guess it doesn’t really measure anything in that field. Looks more like a strategy guideline and a set of techniques.
If you read the section on etymology of the business term, it was referring to the metric of quality control. Basically it means your QC is so good that a bad unit gets shipped only a tiny fraction of the time.
Ligma balls