Shape of the universe at least two angles equal 90°, which makes the sum of the 3 angles greater than 180°. An example of a negatively curved surface would be the shape of a saddle or mountain pass. A triangle drawn on a saddle surface will have the sum of the angles adding up to less than 180°. General relativity explains that mass and energy bend the curvature of spacetime and is used to determine what curvature the universe has by using a value called the density parameter, represented with Omega (). The density parameter is the average density of the universe divided by
Zero degrees of freedom Zero degrees of freedom In statistics, the non-central chi-squared distribution with zero degrees of freedom can be used in testing the null hypothesis that a sample is from a uniform distribution on the interval (0, 1). This distribution was introduced by Andrew F. Siegel in 1979. The chi-squared distribution with "n" degrees of freedom is the probability distribution of the sum where However, if and formula_4 are independent, then the sum of squares above has a non-central chi-squared distribution with "n" degrees of freedom and "noncentrality parameter" It is trivial that a "central" chi-square distribution with zero degrees of freedom