72 American Statistical Association. 



of the article. (See Tables Nos. 4 to 15.) The observations 

 on children of other nationalities were so few in number 

 that it was not considered important to present them in tliis 

 form. To facilitate a comparison of the distribution of the 

 observations at different ages, a second column of figures is 

 given under each age, showing the percentage of the observa- 

 tions occurring at any given height or weight. 



A tabulation of this sort renders it possible to see at a 

 olance the extreme rano-e of variation of the individual obser- 

 vations. In the progress of the work many cases were met 

 with of heights and weights differing so widely from the 

 average measurements of the age to which they belonged as 

 to excite a suspicion of error in the observation. \i\ these 

 cases application was made to the principals of the schools for 

 a confirmation or a correction of the measurements. About 

 forty errors were thus detected, the necessary corrections 

 made, and the tables of averages made more accurate than 

 they otherwise would have been. 



Results. 



The results of the whole investigation are embodied in the 

 tables at the end of the article ; but, in order to facilitate 

 their comprehension, the graphic method has been adopted 

 for their expression, curves having been constructed whicli 

 indicate at a glance the more important conclusions which 

 can be drawn from an examination of the tables. Thus, on 

 Plate I, the ordinates of the two n,pper curves express the 

 average heights for each age of all the children measured, 

 irrespective of the nationality of their parents, the full line 

 representing the boys' rate of growth, and the broken line 

 that of the girls. The two lower curves indicate the average 

 weights in the sauie set of observations. The age is ex- 

 pressed by the row of figures on the line of abscissas, the 

 height in inches by the column on the left (corresponding to 

 the two upper curves), and the weight in pounds by the 

 column on the right of the plate (corresponding to the two 



