For each observation x[i]
, msd
calculates the median of |x[i]-x[j]|/sqrt(s[i]^2+s[j]^2), j!=i
,
that is, the median of differences divided by the estimated uncertainties of the distance.
If s
is a function, it is applied to x
and replicated to length length(x)
; if
a scalar, it is replicated to length length(x)
.
The median scaled difference is a measure of how ‘far’ an individual observation is from
the majority of the other values in the data set. As a rule of thumb, values above
2 are indicative of a suspect (x[i], s[i])
data pair; that is, a value x[i]
that
is remote from a large fraction of the remaining data given its associated standard
error or standard uncertainty s[i]
.