CORRELATION AS APPLIED TO FARM-SURVEY DATA. 
9 
will show that, with the exception of the five between date of sale 
and the other variables, they are all numerically equal to or above 
.90. It has been shown that part, but not all, of the correlation be- 
tween weight and price was due to the date of sale, and since date 
of sale is only an approximate measure of age and length of feeding 
period, it would not be reasonable to expect the net correlation be- 
tween it and the other variables to be perfect. The fact that all the 
net coefficients except these five are so nearly -[-1 or —1, when 
there was every reason to expect perfect correlation, is striking 
proof of the reliability of this method of analysis as well as of the 
accuracy of data such as those under consideration, and is at the 
same time a very good check on the computations. 
In the interpretation of the coefficients care must be taken to dis- 
tinguish between subjective and relative factors, i. e., between cause 
and effect. Most interest is naturally attached to determining to 
just what extent each of the factors under consideration is respon- 
sible for the farmer's loss or gain in his baby-beef enterprise, and 
here there can be no confusion of cause and effect, for all the other 
factors are necessarily causative. Throughout the remainder of the 
investigation the amount of profit or loss is an effect and not a cause, 
and consequently too much weight should not be given to a coefficient 
in which the effect of profit has been taken into account. 
THE APPARENT CORRELATIONS. 
In taking up the discussion of the coefficients themselves, the ap- 
parent correlations between profit and the other five factors are 
first considered : 
Coefficients of correlation. 
Profit 
and 
Weight. 
Profit 
and 
Value 
per hun- 
dredweight. 
Profit 
and 
Value 
of feed, 
Profit 
and 
Cost at 
weaning 
time. 
Profit 
and 
Date of 
sale. 
+.28 
+.23 
-.27 
-.73 
+.14 
These five coefficients should show the average effect of each of the 
five factors on the profit. The coefficient for profit and date of sale 
(+.14) shows that the profit on the calves sold early in the season was 
practically as great as on those sold later. The first three are all of 
nearly the same size, but are too small to indicate more than slight 
relationship. In regard to them we may say, therefore, that in the 
data under consideration: (1) There was a tendency for the heavier 
calves to return a greater profit; (2) there is some correlation be- 
tween price per pound and profit; (3) generally speaking, the farmer 
whose calves consumed feed worth more than the average made a 
profit somewhat less than the average. 
