Degrees of Freedom

Custom Search

Get Free Six Sigma Tools Here

Degrees of Freedom (dof)


To determine the number of measurements that are necessary to make an unbiased estimate of a statistic.


Degrees of Freedom

Reference: Juran’s Quality Control Handbook


A. v (nu) = dF : Represents the degrees of freedom

B. n: Represents the number of observations taken.

C. m: Represents the number of parameters to be estimated. A parameter is a constant defining some property of the density function of a variable, such as the mean or standard deviation.

D. This example is using the equation of the sample standard deviation to illustrate the use of degrees of freedom.

E. The denominator (n-1) represents the degrees of freedom. In this equation, it was necessary to establish only one constant (the sample mean) in order to compute the standard deviation. Therefore, the degrees of freedom is equal to n-1. The number of degrees of freedom will vary according to the statistical test and parameters that are used, but it will always be related to the number of observations and constants. Usually, degrees of freedom are represented by n-1 or n-2.

From Degrees of Freedom to Six Sigma Tools.

Recent Articles

  1. Quality Control Plan - Simple Method To Create Effective Plans

    May 10, 16 09:24 PM

    A Quality Control Plan is a documented description of the activities needed to control a process or product. The objective of a QCP is to minimize variation.

    Read More

  2. Get Free Six Sigma Tools

    May 10, 16 08:49 PM

    The Largest Collection of Free Six Sigma Tools and Training on the Web!

    Read More

  3. Weibull Distribution

    May 10, 16 07:28 PM

    The Weibull distribution is applicable to make population predictions around a wide variety of patterns of variation.

    Read More