What Is Degree of Freedom?

Degree of freedom (df) refers to the number of variables with unlimited values when calculating a certain statistic. Usually df = nk. Where n is the number of samples and k is the number of restricted conditions or variables, or the number of other independent statistics used to calculate a certain statistic. Degrees of freedom are commonly used in sampling distributions.

Statistically, degrees of freedom refer to

1. If there are two variables

,

,and

Then his degree of freedom is 1. Because in fact only

To be truly free to change,

Will be

The choice is limited.

2. Estimate the overall

1 Degree of freedom example 1

One has 4 data (

) Sample, its average

Equal to 5, that is subject to

The conditions are limited. After freely determining the three data of 4, 2, and 5, the fourth data can only be 9, otherwise

. So the degrees of freedom here

. By extension, the freedom of any statistic

(K is the number of restrictions).

2 Degree of freedom example 2

If you cut a grapefruit with a knife, cut 3 knives along the meridian at the North Pole to get 6 corners. These 6 corners can be regarded as 3 pairs. The average angle of the six corners must be 60 degrees. Among the three corners of the half, only two can be freely selected. Once the two values are determined, the third corner will be uniquely determined. When the sum is known, the number of division angles is one greater than the number that can be freely divided.