48 BULLETIX 1300, U. S. DEPARTMENT OF AGRICULTURE 
prices of the same and preceding falls (positive effects). The inter- 
pretation is that the packers' demand is based on their judgment of 
the scarcity of hogs in the country (low past breeding) and of the 
prospective hog supply, as influenced by corn prices. The actual 
marketing of hogs is probably to some extent responsible for these 
correlations as an intermediary factor between breeding and hog price 
and possible also between corn price and hog price. A hog price 
which does not permit a profit, owing to the price of corn, tends to 
cause a drop in shipments to market. 
Winter hog price is similarly represented as influenced by the breed- 
ing of the second preceding year (negative) and the prices of the two 
preceding fall corn crops (positive). 
The amount of breeding (most of which occurs late in the fall) is 
represented as determined largely by the factors which determine the 
profits from hog raising during the summer and preceding winter, 
namely, the summer and winter hog prices (positive) and the price of 
the two preceding corn crops — those on which the hogs were raised 
and fattened — (negative). The price of the current crop (also 
negative) and the amount of breeding of the preceding year (positive) 
are also represented as factors. Cheap corn stimulates fall breeding. 
The correlation between successive years can be interpreted as due 
to a tendency among breeders to stay in the business. 
While the diagram of relations may appear somewhat complex, 
only 14 paths of influence are represented — 1 back of corn price, 4 
back of summer hog price, 3 back of winter hog price, and 6 back of 
breeding. Using the letters indicated in the diagram for the 13 cor- 
responding unknown path coefficients (the coefficient for the path 
corn crop to corn price, is simply the correlation —0.80), the fol- 
lowing equations can be formed. (Table 9.) The correlations with 
summer weight and second following whiter slaughter are given in 
parentheses as indicators of the correlations involving breeding. 
In both cases, it must be remembered, the breeding of the preceding 
vear is also considered to be a factor. 
Table 9. — The equations ex-pressing the correlations within the central system of 
variables, corn price (P), summer hog price (S), winter hog price (W), and hog 
breeding (B) as the resultant of path coefficients 
[Actual correlations are given in the second column, breeding being represented in parentheses by summer 
weight of the same year and winter pack of the following year. The calculated correlations are given in 
the last column] 
Calcu- 
lated 
value 
r 8P =+0. 18 =a 
+0. 15 
r BP =(-0.43, -0. 32) =a+6r SP 
-0.40 
r WP =+0.40 = fc._ 
+0.45 
r. P ' =+0. 66 =/i-Hr BP -- 
+0.66 
Tbp 1 =(-0. 51, -0. 53) = 6r B p'+c+dr W P+/rBP- 
-0.37 
r W p' = +0. 56 . = Z+mr BP _ 
+0.51 
r.P 11 =+0. 29 =ir BP i+jr BT 
r B p" =(+0. 13, -0. 0l) = 6r 9P "+drwp I +e+/r B p I 
+0.31 
+0.25 
r W p" =+0.20 =mr BP ' 
+0.24 
r 9P ni =-0.04 =?>BP"+jr B p 1 -- 
+0.05 
r BP in =(+0.22).. =6r 8P m+drwp"+/r BP " 
+0.20 
r W p"' = -0. 31 =7nr B p" 
-0. 16 
rgp iv =.. =ir B p'"+jr BP " 
-0. 18 
r B p ,v =.. =6r 8 p^+drwp" , +/r B p" 1 
-0. 15 
Twp iv =.- =7«r I1 p'" 
-0. 13 
r BB > =(+0.05, +0.21) = [r Br >(dl+e)+r Br (bh+c+dk)+bi+ft/[l-bj-dm] 
+0.07 
r.p' =(-0.68, -0. 50)=/ir B p+i+/r BB >.__ 
-0.63 
