Returns "fitted values" of a (standardized) major axis fit.
# S3 method for sma
fitted(object, type = "fitted", newdata = NULL, centered = TRUE, ...)Object of class sma.
Either 'residuals', or 'fitted'.
New data for which to provide fitted values.
Logical. If TRUE (the default) returns the zero-centered fitted values.
Further arguments are currently ignored.
"Fitted values" are calculated using y+bx for SMA or by+x for
MA (see Warton et al. 2006, especially Table 4). Note these values are
calculated differently to ordinary linear regression, and they cannot be
interpreted as predicted values. The "fitted values" should be interpreted
as measuring how far along the fitted axis each point lies, and are used in
checking assumptions (via residual vs. fitted value plots).
Fitted values may be computed for new data, using the newdata
arguments. Be aware that the names of the variables need to be the same as
in the data used in the original model fit. Also, if the original fit used
log='xy', for example, this transformation will also be applied to
your newdata (so don't do the transformation yourself).
Warton D. I., Wright I. J., Falster D. S. and Westoby M. (2006) A review of bivariate line-fitting methods for allometry. Biological Reviews 81, 259-291.