This function calculates the percent prediction error in a sample
Usage
ppe(true, pred, abs = TRUE)
Arguments
true
a numeric vector representing the true value on which a prediction (pred) will be based
pred
a numeric vector with the predicted values, must be equal length to 'true'
abs
a logical value indicating whether to calculate absolute values for ppe, default is TRUE
Value
Function returns a list of results, including the a list of all the precent prediction errors, along with the mean, 95 percent confidence intervals, range, and standard deviation.
Details
This function calculates the percent prediction error (ppe) as a scaled residual, so:
ppe=((true-pred)/pred)*100
References
Campione, N. E. and Evans, D. C. (2012) A universal scaling relationship between body mass and proximal limb bone dimensions in quadrupedal terrestrial tetrapods. BMC Biology, 10, 60.
Smith, R. J. (1980) Rethinking allometry. Journal of Theoretical Biology, 87, 97-111.