Haggerty: Study in Arithmetic 



471 



Just what dependability should be required is an open ques- 

 tion. In setting his new scores Mr. Courtis assumes 100 per cent 

 accuracy. This is a high requirement which few men attain in 

 any field, even that of exact science. Elementary school children 

 will hardly reach it with ordinary effort. The excessive effort 



lOO I 



80 • 



40 































o 

 t- 



<ri 

 O 

 CQ 



oc 

 o 



CITY 1 



INDIVIDUAL 



1 



z 



3 



4 



5 



6 



7 





9 



10 



11 



12 



13 



14 



13 



16 



ir 



18 



19 



FIG. 43 DEPENDABILI TY "^'^"^^ PER CENT SERIES B GRADE 7 MULTIPLICATION 



14 15 16 17 



FIG. 44 DEPENDABIUTY 



R GHTS 

 ATTEMPTS 



'ER CENT SERIES B GRADE ? 



necessary to attain such skill is hardly repaid by the returns. 

 Adding machines and methods of checking results easily make 

 up the deficiency. Seventy per cent was the mark in addition for 

 my college class. This was also the record for Boston eighth grade, 

 but no Indiana city reached this mark, nor do any other of Courtis' 

 published scores. In view of these facts a 75 per cent depend- 



