4 ms·

Can someone please explain what 5 sigma signifies? Edit: “Evidence” usually means a 3-sigma signal, which existed last December, “Proof” would be a better way

Can someone please explain what 5 sigma signifies? Edit: “Evidence” usually means a 3-sigma signal, which existed last December, “Proof” would be a better way to describe a 5+ sigma signal, if that’s what the combined CMS/ATLAS data shows - http://www.math.columbia.edu/~woit/wordpress/?p=4809 http://www.math.columbia.edu/~woit/wordpress/?p=4809

mkramlich 14y ago
> Can someone please explain what 5 sigma signifies? It means a statistically very very significant number of physicists are getting laid tonight, around the world. ;)
kinghajj 14y ago
I believe 5 sigma is the threshold for "proof" in the physics community.
caladri 14y ago
99.999% confidence.
- InclinedPlane 14y ago
  Actually, it's 99.99994% confidence (1 in 1.7 million chance of error).
InclinedPlane 14y ago
5 sigma is the traditional limit of significance for new discoveries in particle physics. If you have data showing the existence of a new particle or phenomenon at 5 sigma you publish and you announce and you start saying "this thing exists" instead of "this thing may exist".
btilly 14y ago
5 sigmas means that a model without a Higgs would have their actual data set be 5 standard deviations out from what is expected. That corresponds to 99.99994% confidence on a standard null hypothesis test, and is the usual threshold in physics for considering something proven.
drostie 14y ago
They just announced 5.1 sigma, and on a normal distribution that would mean that it is 99.999966% certain, so that there is about a one-in-three-million chance that this is due to random chance, otherwise there is some sort of excess here due to a new particle.
yureka 14y ago
This physics-exchange post does a great job at explaining why 5.0 sigma is required as a threshold for discovery in particle physics, http://physics.stackexchange.com/questions/8752/standard-deviation-in-particle-physics http://physics.stackexchange.com/questions/8752/standard-dev...

mkramlich 14y ago

> Can someone please explain what 5 sigma signifies? It means a statistically very very significant number of physicists are getting laid tonight, around the world. ;)

kinghajj 14y ago

I believe 5 sigma is the threshold for "proof" in the physics community.

caladri 14y ago

99.999% confidence.

InclinedPlane 14y ago
Actually, it's 99.99994% confidence (1 in 1.7 million chance of error).

InclinedPlane 14y ago

5 sigma is the traditional limit of significance for new discoveries in particle physics. If you have data showing the existence of a new particle or phenomenon at 5 sigma you publish and you announce and you start saying "this thing exists" instead of "this thing may exist".

btilly 14y ago

5 sigmas means that a model without a Higgs would have their actual data set be 5 standard deviations out from what is expected. That corresponds to 99.99994% confidence on a standard null hypothesis test, and is the usual threshold in physics for considering something proven.

drostie 14y ago

They just announced 5.1 sigma, and on a normal distribution that would mean that it is 99.999966% certain, so that there is about a one-in-three-million chance that this is due to random chance, otherwise there is some sort of excess here due to a new particle.

yureka 14y ago

This physics-exchange post does a great job at explaining why 5.0 sigma is required as a threshold for discovery in particle physics, http://physics.stackexchange.com/questions/8752/standard-deviation-in-particle-physics http://physics.stackexchange.com/questions/8752/standard-dev...