# Adjusting degrees of freedom

## !ADJUST and !DF

!DF ` n `
alters the error degrees of freedom from `nu`
to `nu + n`. This qualifier might be used
when analysing pre-adjusted data to reduce the degrees of freedom
(` n` negative) or when weights are used in lieu of actual data
records to supply error information (` n` positive). The degrees
of freedom is only used in the calculation of the residual variance
in a univariate single site analysis. The option will have no effect
in analyses with multiple error variances (for sites or traits)
other than in the reported degrees of freedom.
Use
!ADJUST ` r `
rather than
!DF ` n `
if ` r ` is not a whole number.
Use
!YSS ` r `
to add ` r ` to the total sum of squares.
It would be usual to also increase the degrees of freedom.
For example, when analysing summarised data, you may have an independent estimate of the variance.
To include that variation to the analysis, use !YSS 100 !DF 20
say, to add the equivalent of 20 observations with a variance of 5.
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