Statistics Dictionary
To see a definition, select a term from the dropdown text box below. The statistics
dictionary will display the definition, plus links to related web pages.
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Degrees of Freedom
The term degrees of freedom (df) refers to the number of independent sample points used to compute a
statistic minus the number of
parameters estimated from the sample points.
For example, consider the sample estimate of the population variance ( s2 ):
where X i is the score for observation i in the sample,
X is the sample estimate of the population mean, and
n is the number of observations in the sample.
The formula is based on n independent sample points and one estimated population parameter (X).
Therefore, the number of degrees of freedom is n minus one. For this example,
df = n - 1
