Haggerty: Studies in Arithmetic 



107 



Accuracy. — Table IV shows in a similar way the gain made 

 by each group in May in accuracy. Thus the unpracticed group 

 in the fifth grade gained 30 per cent in addition and the practiced 

 group 37 per cent, making a gain for the practiced over the un- 

 practiced of 7 per cent. In subtraction this gain was 20 per cent, 

 in multiplication 5 per cent, while in division the practiced group 

 fell 1 per cent below the unpracticed group. In the sixth grade 

 the gain of the practiced over the unpracticed is in addition 8 

 per cent, in subtraction 19 per cent, in multiplication 2 per cent, 

 and in division 6 per cent. The greatest gain in accuracy is in 

 subtraction. The gains in both grades are much the same in 

 each operation except in division, where the practiced group's 

 gain over the unpracticed is 7 per cent greater than the corres- 

 ponding gain in the fifth grade. 



TABLE IV.— ACCURACY PER CENT OF GAIN (IN MAY OVER 

 SEPTEMBER) IN ACCURACY OF PRACTICED AND 

 UNPRACTICED GROUPS 





Unpracticed 



Practiced 



Of Practiced 



over 

 Unpracticed 



Grade 5 









Addition 



30 



37 



7 



Subtraction 



29 



49 



20 



Multiplication 



26 



31 



5 



Division 



43 



42 



— 1 



Grade 6 









Addition 



12 



20 



8 



Subtraction 



2 



21 



19 



Multiplication 



18 



20 



2 



Division 



28 



34 



6 



Tables V and VI give the medians for each group in attempts 

 and rights together with the gain of each and the gain of the 

 practiced over the unpracticed. 



