THE CHANCES OF DEATH 



95 



into five component frequency curves. The data which he 

 used were furnished by the d^ line of Ogle's life table, 

 based on the experience of 1871 to 1880 in England. This 

 line gives the deaths per annum of one thousand persons 

 born in the same year. The first component which he sepa- 

 rated was the old age mortality. This is shown by the 

 dotted curve having its modal point between 70 and 75 

 years, at the point lettered Oj on the base of the diagram. 



YCAns or urc 

 Fio, 25. — Showing Pearson's results in fitting the dx line of the life table with 5 skew 

 freauency curves. Plotted from the data of Pearson's original memoir on "Skew Variation" 

 in Phil. Trans. Roy. Soo. 



This component, according to Pearson's graduation, 

 accounted for 484.1 deaths out of the total of 1,000, or 

 nearly one-half of the whole. Its range extends from 

 under 20 years of age to the upper limit of life, at approx- 

 imately 106 years. The second component includes the 

 deaths of middle life. This is the smooth curve having 

 its modal point between 40 and 45 years at the point on 

 the base marked Oj. Its range extends from about 5 

 years of age to about 65. It accounts for 175.2 deaths 

 out of the total of 1,000. It is a long, much spread out 



