FINAL CONCLUSIONS	443
examinee's measurements with a standard series based on
simple averaging and specifying the type.
 4.	Simple practical methods are suggested for recording
either by a numerical coefficient or by a psychographic
chart or ^c profile ' the essential temperamental character-
istics and ^c type ' of individual persons.
 5.	By means of the methods described a large number
of persons of both sexes and of different ages have been
assessed for the bipolar factor which appears to underlie
the difference between the so-called introverted and extra-
verted types.    For each group examined the distribution
proves to be not bimodal but continuous, the mixed or
relatively  well-balanced   type   being  commonest   of   all.
For the  entire group  the distribution is  slightly asym-
metrical,   showing   a   small   excess   of   extraverted   cases.
Within the component groups the amount of extraversion
differs  according to  age,  sex,   and  social  or  intellectual
status,   being  greater  among younger   children  and  less
in older or more intellectual males.    In view of the age,
history, and physical peculiarities of many of the introverts,
it is suggested that introversion rather than extraversion is
usually the positive characteristic, and may not infrequently
be  a late pathological development rather than a direct
manifestation of inborn temperament.    In any case, the
'factors ' undoubtedly represent highly mixed and complex
groups of causes.
 6.	For  statistical  purposes it is * proposed to measure
approximation to type, not by the saturation coefficient as
it stands, but by its inverse hyperbolic tangent.    With this
transformation the frequency curve approximates closely
to  the normal.    Thus  the  more  typical  introverts  and
extraverts appear in the main to be merely extreme cases
taken from the opposite tail-ends of a normal or nearly
normal distribution.