Although the average weights of the boys and girls for the 

 two-year period are nearly identical, being respectively 105.71 

 and 105.73 pounds, the boys show a greater amount of variation 

 in weight than the girls. The standard deviation for the boys 

 is 17.25 pounds, and for the girls 16.00 pounds. Moreover, 

 the interquartile range that is, the difference between the 

 third and first quartiles is 23.72 pounds for the boys, and only 

 19.83 pounds for the girls. Since one-half of the children are 

 included within these limits, it is clear, as was the case with the 

 heights, that the boys show a greater variability than the girls. 



GRAPH C 



Number of Boys and Girls, Ages 14 to 16, for Each Five Pounds 

 of Weight ; Also at Average, Median and Quartile Weights 



10- 115- 120- 125- 130- 135- 140- 145- 160- 155- 160- 165- 170- 

 jhts in Five Pound Groups 



These facts are portrayed in Graph C. The girls cluster 

 more closely about the average than the boys. It is interesting 

 to note that the position of the first quartile point for boys 

 is 93.31 pounds, which is considerably below the corresponding 

 point for the girls, namely, 95.18 pounds. On the other hand, 

 the third quartile point for boys is 117.03, as against 115.01 

 for girls. These differences are even more marked when we 

 observe the relation of weights of boys to those of girls during 

 the two individual years. This will incidentally show the 

 amount of gain in weight of boys and girls during the year. 



11 



