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• centage who married at ages greater than any specific age selected

from the horizontal scale of the chart.

Fig. 151 gives an example of a class of information which can be shown to very great advantage by the use of cumulative frequency curves. In an annual report of a railroad a tabulated statement of the number of miles of different weights of rail in use at the end of the fiscal year makes the information difficult for the stockholder to interpret. Putting the data in the form of a curve like Fig. 151 lets the stockholder see at once just what conditions are on his road, in so far as rail weight is concerned. Thus, in Fig. 151, the stockholder may see at a glance that a very small percentage of the rails on this railroad weigh in excess of 75 pounds per yard, and that only about half of the rails weigh more than 70 pounds per yard. In order to compare different years it would be well to have a chart of this kind printed in the annual report, with curves for different years plotted on the same co-ordinate ruling, so that the stockholder could see by the change in the shape of the curves just what has been done toward replacing light rails with heavy rails. If desired, rail-weight curves for different railroad systems could be shown in the same chart, so that the stockholder might see how his railroad compares with others in the matter of rail weights.

Data of Elmer Rittenhouse, of the Equitable Life Assurance Society

Fig. 149. Change Since 1880 in the Death Rate of Americans at Various Ages

The increase in death rates for ages over forty is here shown in great contrast with the decrease in death rates for ages less than forty. The heavy zero line and the arrows pointing upward and downward make misinterpretation almost impossible

It would have been better if Fig. 151 had, at the lower left-hand corner, the words "more than", with an arrow pointing horizontally to the right as can be seen in Fig. 158. In cumulative frequency curves