“…In January, 1926, the value of hogs was obtained from about half of the list of crop reporters on the basis of all hogs, as shown in Table 17; from the other half of the list on the basis of three subclasses; namely, ( 1) pigs under 6 months, (2) sows and gilts bred or to be bred for spring pigs, and (3) all other hogs 6 months old and over, including boars. The average price of all hogs was higher when determined on the basis of the three subclasses.…”