----
Total 500

This distribution includes all pupils, from the beginners in the first
grade to the older boys in the seventh and eighth grades. It is
certain, however, that differentiated instruction for vocational
purposes is not possible or advisable for the younger children.
According to the commonly accepted view among educators, vocational
training should not be undertaken before the age of 12 years, and many
believe that this is too early. In an elementary school of 1,000
pupils there would be about 80 boys 12 years old and over. Applying
to this number the ratios given in the previous table we obtain the
following:

_Number of boys who will enter_
Manufacturing and mechanical occupations 35
Commercial occupations 16
Clerical occupations 13
Transportation occupations 9
Domestic and personal service occupations 4
Professional occupations 2
Public service occupations 1
---
Total 80

The industrial group includes all of the skilled trades and most of
the semi-skilled and unskilled manual occupations. The skilled trades
are usually grouped in four main classifications: metal trades,
building trades, printing trades, and "other" trades, these last
comprising a number of small trades in each of which relatively few