THE  VOCATIONAL  VALUE  OF  TESTS  175
discover  these  facts.  Until  they  are  known,  no  intelligent
choice  can  be  made.  For  instance,  when  a  boy,  either
"within  the  organization  or  without,  applies  for  admission
to  the  apprentice  course,  a  course  which  occupies  a  period
°f  years  and  which  is  very  costly,  the  question  as  to
"whether  this  boy  has  the  necessary  prerequisite  education
and  the  natural  ability  to  succeed  is  sure  to  arise.  He  has
undoubtedly  had  some  education,  but  whether  his  education ­
  has  gone  far  enough,  or  whether  he  has  profited  by  his
educational  opportunities  to  the  extent  of  being  able  to
handle  the  necessary  mathematical  problems,  is  a  matter
which  must  be  carefully  determined.  In  addition  to  this
it  is  necessary  to  know  whether  the  boy  possesses  the
natural  ability  which  will  enable  him  to  succeed  as  an
a pprentice.  How  shall  these  two  very  important  facts  be
determined?  This  is  just  the  question  for  which  psychological ­
  tests  provide  the  answer.
All  tests  may  be  divided  roughly  into  two  kinds:  Those
designed  to  discover  an  individual’s  degree  of  innate
ability  in  certain  directions,  and  those  designed  to  measure
the  extent  and  quality  of  an  individual’s  previous  training
and  acquired  ability.  This  distinction  is  by  no  means  a
dear  and  sharp-cut  one,  for  every  test  whatsoever  involves
to  some  extent  both  natural  or  innate  ability  and  the
ability  due  to  training  and  education.  The  tests  described
J n  preceding  chapters  have  already  made  this  fact  clear.
However,  for  practical  purposes,  tests  may  be  divided  into
these  two  general  kinds.  When,  therefore,  the  question  of
■Vocational  training  or  selection  arises,  the  application  of
these  tests  makes  it  possible  to  discover  what  the  natural
and  acquired  abilities  of  an  individual  are  and  under
which  of  the  four  heads  given  he  is  to  be  classified.  Let
Us  take,  for  instance,  the  case  of  the  candidate  for  appren-