Hello All,

    Using the standard "summary" function in 'R', I ran across some odd
behavior that I cannot understand.  Easy to reproduce:

Typing:

   summary(c(6,207936))

Yields::

   Min. *1st Qu.  Median    Mean 3rd Qu.    Max.*
      6   *51990  104000  104000  156000  207900*


    None of these values are correct except for the minimum.  If I perform
"quantile(c(6, 207936))", it gives the correct values.  I originally
presumed that summary was merely calling "quantile" if it saw a numeric, but
this doesn't seem to be the case.
    Anyone know what's going on here?  On a related note, what is the
statistically correct answer for calculating the 1st quartile & 3rd quartile
when only 2 values are present?  I presume one takes the mid-point between
the median (also calculated) and the min or max.  So in this case, 51988.5
for 1st & 155953.5 for 3rd (which is what quantile calculates).  But taking
25% & 75% of the sum of the 2 also seems "reasonable".  Either way,
"summary" is calculating the wrong number, and most disturbing is that it
mis-calculates the max.

                                            Regards,
                                                    Mike


"Telescopes and bathyscaphes and sonar probes of Scottish lakes,
Tacoma Narrows bridge collapse explained with abstract phase-space maps,
Some x-ray slides, a music score, Minard's Napoleanic war:
The most exciting frontier is charting what's already here."
  -- xkcd

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