Calculates the average (mean) absolute deviation from the sample mean.
Usage
aad(x, na.rm = TRUE, ...)
Arguments
x
A numeric vector containing the observations.
na.rm
A logical value for na.rm, default is na.rm=TRUE.
...
Additional arguements (currently ignored)
encoding
UTF-8
Details
The statistical literature has not yet adopted a standard notation for the "Mean Absolute Deviation" and the "Median Absolute Deviation". As a result, both statistics have been denoted as "MAD", which may lead to confusion once they may produce different values.
The R mad by default computes the "Median Absolute Deviation"; to obtain the "Mean Absolute Deviation" one has to use mad(x, constant = 1).
Thus, the function aad will calculate the "Mean Absolute Deviation"--or "Average Deviation (AD)" as proposed by Garrett, who defines it as "the mean of the deviation of all the separate scores in the series taken from their mean (occasionally from the median or mode)", (1971, p. 481).
References
Garrett, Henry (1982) Statistics in Psychology and Education. 6th, Paragon.