backfit function

Calculation of backfit values from a fitted dose-response model

By inverse regression backfitted dose values are calculated for the mean response per dose.

backfit(drcObject)

Arguments

• drcObject: an object of class 'drc'.

Returns

Two columns with the original dose values and the corresponding backfitted values using the fitted dose-response model. For extreme dose values (e.g., high dose ) the backfitted values may not be well-defined (see the example below).

References

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Author(s)

Christian Ritz after a suggestion from Keld Sorensen.

See Also

A related function is ED.drc.

Examples

ryegrass.LL.4 <- drm(rootl~conc, data=ryegrass, fct=LL.4())

backfit(ryegrass.LL.4)