-Sa 
lt will be noted that the process can be described up to 
this point without any reference to income. We may regard the 
states of the system represented by the elements of the matrix 
as "grqdes" or "age" - possibly carreer age or age in earning 
life, although in conformity with Champernowne we referred to 
them as income classes. 
We have now to define the income In relation to the class 
intervals of the matrix; The lower limit of class 1 is 
taken to be the minimum income. We may choose the income 
units such that the minimum income is unity, i.e. on the 
logarithmic scale it is zero. The income y^ at the lower 
limit of successive income classes K is defined by 
Jk - 
e* h 
or In y K = Kh 
c*-) 
where h is the size of the class interval on the log scale 
D 
TT 
The dilfLculties arising from the discrete representation of 
a continuous income variable in the matrix do not concern 
us here. See £,oJ p. 62. 7Z*, / 
'/ 
' 
^ / 
b * C i- a 7 *1 c- by 
■'%