Solid angle at an average angular diameter of 0.5334 degrees or 9.310 radians. The Moon is seen from Earth at an average angular diameter of 9.22 radians. We can substitute these into the equation given above for the solid angle subtended by a cone with apex angle : The resulting value for the Sun is 6.807 steradians. The resulting value for the Moon is 6.67 steradians. In terms of the total celestial sphere, the Sun and the Moon subtend "fractional areas" of 0.000542% (Sun) and 0.000531% (Moon). On average, the Sun is larger in the sky than the Moon even though it
Degrees of freedom (statistics) Gosset did not actually use the term 'degrees of freedom', he explained the concept in the course of developing what became known as Student's t-distribution. The term itself was popularized by English statistician and biologist Ronald Fisher, beginning with his 1922 work on chi squares. In equations, the typical symbol for degrees of freedom is "ν" (lowercase Greek letter nu). In text and tables, the abbreviation "d.f." is commonly used. R. A. Fisher used "n" to symbolize degrees of freedom but modern usage typically reserves "n" for sample size. Geometrically, the degrees of freedom can be interpreted as the dimension