Degrees of freedom (statistics)

In statistics, the term degrees of freedom is used in two distinct ways.

Parameters in probability distributions

The probability distributions of residuals are often parametrized by these numbers of degrees of freedom. Thus one speaks of a chi-square distribution with a specified number of degrees of freedom, an F-distribution, a Student's t-distribution, or a Wishart distribution with specified numbers of degrees of freedom in the numerator and the denominator respectively.

Related Topics:
Probability distribution - Chi-square distribution - F-distribution - Student's t-distribution - Wishart distribution

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In the familiar uses of these distributions, the number of degrees of freedom takes only integer values. The underlying mathematics in most cases allows for fractional degrees of freedom, which can arise in more sophisticated uses.

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