VARIABILITY OF A SINGLE CHARACTER I15 
feet, or what not — and the “class marks’’! fixed, then the 
student is ready for measurements. The next question is where 
to record the various individuals measured. lor example, sup- 
pose in measuring corn we have adopted the scheme, 4.0, 4.5, 
5.0, 5.5, 6.0, 6.5, 7.0, 7.5, etc. We will rarely find an ear that 
measures exactly on the even inch or half inch. Most of them 
will fall somewhere between these various marks and will need 
to be assigned to one group or another somewhat arbitrarily. 
Now the rule is to assign to the nearest group. Thus suppose 
an ear measures 7} inches; it would be put into the 7.0-inch 
class because it is nearer 7 inches than it is to any other measure- 
ment of our scheme. Should it measure 6% inches, it would 
also go into the 7.0-inch class, and in doing so it would correct 
the slight error made in putting the other ear into a class too 
short for it. On the principle that as many will be too long as 
will be too short, we depend upon the law of chance? to keep 
our errors even. 
On the same principle, if the ear should read 72, it would go 
into the 7.5-inch class; but if it should be 7}, it would stand 
exactly halfway between the two classes, and here a careful de- 
cision must be made as to where it should be put. As it stands 
midway between 7 and 7.5 there are no more reasons for its 
going one way than the other, and in choosing a scheme of 
measurements it is well to avoid a scale that is likely to make 
too many fall upon this middle point. 
There are but two things to be done with these midclass 
measures. They can all be put into the class above them, on 
the principle of the business man that calls half a cent a whole 
cent and then discards all smaller fractions; or, what is more 
accurate, every alternate measurement of this kind may be put 
once above and next below; that is, the first time a 7.25 
measurement occurs it may be called 7.5, and then, to offset the 
1 The class marks are the various measurements, as 4 inches, 4.5 inches, 
5 inches, etc., that make up the scheme of measurements. 
2 Principles of Breeding,” p. 365. 
