AVGMED: Median average of a series of numbers
syntax: AVGMED(n, x1, x2, x3, ...) or
AVGMED(<filename>)
Returns the median average of a series of numbers. Input consists of a series
of numbers with the first argument specifying the number of elements in the
series or a single argument specifying the name of the plain text file
containing the series of numbers with each element in the file seperated by
spaces or starting at a new line.