In Fig. 160 is shown a chart which may help to make clearer the general principles used in drawing the charts seen in Fig. 157, Fig. 158 and Fig. 159. Fig. 160 shows the appearance of the curves if there are the same number of orders in each class or group and if all classes or groups are of uniform size. It makes no difference in the shape of the curves how many orders there may be if those orders are always uniformly distributed throughout the whole length of the horizontal scale of the chart. It would perhaps have been better if Fig. 160 had been so drawn that the length of the vertical scale would be the same as the length of the horizontal scale. The actual shape of the curve line referring to the percentage of business or the percentage of the total number of pieces would then be free from any possible distortion which it may have received because of the vertical scale being of less total length here than the horizontal scale.

It is especially interesting to compare Fig. 160 with Fig. 159. In Fig. 159 the reader may easily see for himself that there are many more small orders than there are large orders, because the pins are largely concentrated toward the left-hand side of the chart. It is this concentration at the left-hand side which has so greatly affected

Fig. i6o. Chart to Show the Theoretical Shape of Cumulative Curves for the Percentage of Total Orders and the Percentage of Total Business if There Is a Uniform Number of Orders in Each Class or Group