442	THE  FACTORS OF THE MIND
the distribution of innate temperamental tendencies may
be treated as normal. Provisionally, and until more exten-
sive surveys have been carried out, we might perhaps
accept the converted z-distribution (last line of Table VI)
as indicating the theoretical distribution of temperamental
variations. If, however, the variations are measured by a
coefficient of correlation (or its equivalent) then we must
be prepared to accept distortions of the kind described above.
C.    summary
 1.	Reasons have been advanced for believing (a) that the
temperamental   factors   deducible   from   assessments   for
groups of normal adults and children are essentially the same
as those previously deduced from assessments for neurotic
and delinquent children referred for clinical examination,
and (b) that, whether persons or traits are correlated, the
main type-factors  (i.e.  all significant factors  except  the
first) remain virtually the same throughout.
 2.	Explicit calculation further shows that this equiva-
lence of * person-factors'  and ' trait-factors'  still holds
good, even (a) when the correlations are derived from a
relatively unselected group of normal persons,  differing
in  general  or  average  emotionality,   instead  of  from   a
selected  group,   relatively  homogeneous  as  regards  this
general factor ;   (b) when correlations are used instead of
covariances;  and (c) when the simple summation method
is employed instead of the more laborious method of least
squares.    Criticisms   of  this  so-called  ' reciprocity  prin-
ciple ^? are shown to be inconsistent with the critic's own
experimental results.
 3.	Explicit calculation verifies (what had previously been
proved algebraically) that with the summation method the
correlation of a person's measurements with the average
measurements for the type is virtually identical with his
saturation coefficient.    It follows that, for practical pur-
poses, in order to estimate the degree to which the several
persons approximate to a given type, it is no longer necessary
to calculate all the intercorrelations and then to perform
a systematic factor-analysis ; it is sufficient to correlate the