the extremes is small, as might be expected. The distribution 

 follows quite closely the curve of error. It is fairly symmetri- 

 cal, and the largest numbers cluster around the average. The 

 mean and the median for boys are identical, both being 61.99 

 inches; in the case of girls, also, the figures agree quite 

 closely, the mean being 61.35 inches, and the median only .04 

 inch less. 



The distribution of heights between the first and third 

 quartile points indicates that half of all the boys are found 

 between the limits 59.91 and 64.17 inches, a range of 4.26 

 inches. Half of the girls, however, extend over a range of 

 only 3.05 inches between 59.88 and 62.93 inches. These 

 figures show a greater variability in the height of boys as com- 

 pared with that of girls. This is borne out further by the fact 

 that the standard deviation, which is the measure of variability, 

 is 3.08 inches for boys, and 2.38 inches for girls. 



These facts are illustrated in Graph A, which portrays the 

 distribution of the heights of the boys and girls for the two- 



GRAPH A 



Number of Boys and Girls, Ages 14 to 16, at Each Inch of 

 Height ; Also at Average, Median and Quartile Heights 



