Dots for the different years placed on such a chart, after the general manner of Fig. 119, will appear so widely scattered over the whole field that the reader will find it almost hopeless to draw any general conclusion from the arrangement of the dots. Though the dots indicate by their position a general tendency

GRAPHIC METHODS

for exports to decrease as prices increase, there would seem to be so many complex factors entering into the relation that no very general law of dependence can be proved.

It can be seen from inspection that the relations existing between the two curves of Fig. 118 are much closer than exist between the two curves of Fig. 117. It is unfortunate that in Fig. 118, as well as in Fig. 117, the chart was carelessly prepared so that the two curves do not have the same zero line.

Courtesy of Pennsylvania Farmer

Fig. ii8. The Average Price of Apples in the United States as Compared with the

Total Supply

Here again an inverse relation is indicated, but the chart has carelessly been made with the two vertical scales starting from separate zero lines so as to cause distrust by the reader. The chart is printed showing a finely ruled co-ordinate background, though only every tenth line is desirable for the reader. The use of more lines than necessary should be avoided as it tends to cause confusion. See Fig. 119 as another method of charting the same data

In order to determine just how closely the price of apples depends upon the supply, Fig. 119 was prepared from the data of Fig. 118. Though the dots in Fig. 119 represent a rather long series of years, they nevertheless have a fairly symmetrical arrangement and the general tendency might be approximated by a smooth curve drawn as shown.