Are you comfortable in your retirement? If you have a $500,000 portfolio, download the guide for retirees by Forbes columnist and money manager Ken Fisher's firm. It's called "The 15-Minute Retirement Plan." Click Here to Download Your Guidel FISHER INVESTMENTS- Dow Jones Reprints: This copy is for your personal, non commercial use only. To order presentation-ready copies for distribution to your colleagues, clients or customers, use the Order Reprints tool of the Bottom of any article or visit wwwdjzoprints.com See a sample reprint in PDF format. Order a reprint of this article now THE WALL STREET JOURNAL WAL.com THE NUMBERS GUY ! July 6, 2012, 6:52 p.m. ET How to Be Sure You've Found a Higgs Boson By CARL BIALIK The physicists who announced the likely discovery of the long-sought Higgs boson particle this week were operating according to an extremely high standard of certainty. As was widely reported, in order to achieve discovery status their experiment had to clear a threshold of "five sigmas" of statistical significance. What precisely the five-sigma mark means, however, wasn't always clearly explained in the coverage of a ground-breaking development that could explain how particles have mass and, by extension, why planets and all other objects exist at all. That is partly because the five-sigma concept is somewhat counterintuitive. It has to do with a one-in- 3.5-million probability. That is not the probability that the Higgs boson doesn't exist. It is, rather, the inverse: If the particle doesn't exist, one in 3.5 million is the chance an experiment just like the one announced this week would nevertheless come up with a result appearing to confirm it does exist. Agence France-Presse/Getty Images In other words, one in 3.5 million is the likelihood of Part of the Large Hadron Collider in Geneva that finding a false positive-a fluke produced by random scientists used to discover the Higgs boson particle. statistical fluctuation-that seems as definitive as the findings released by two teams of researchers at the CERN laboratory in Geneva. The Numbers Guy blog The Particle Proof This is a very high burden of proof as far as science Previously in the Numbers Guy goes. For many medical experiments, researchers need Browser Wars Escalate merely to clear two sigmas. Sigmas don't scale in a Kids Can Be Costly Long After 18 linear way: A two-sigma result can have as much as a Sports Results That Leave Final Score 5% chance of occurring as a false positive. Three Unclear sigmas, needed to cite evidence-but not discovery-of a new particle in physics, correspond to a one-in-741 chance