450 



Indiana University Studies 



high per cent of variability means that the class is loosely graded, 

 the same class containing children of very nneqnal achievement. 

 Just how small the per cent of variability should be for good 

 s<^hool Avork is as yet an undetermined fact. Mr. Courtis declares 



70- 



flG. 21 - VARI\BU-m- SERIES B GRADE b ADnmON 



that '^the smaller the variaMliiy, oilier things heing equal, the 

 more efficient the teaching. Varialjilities of 12 per cent to 15 per 

 cent represent good tvork under present conditions. In the near 

 future these ivill prohably he reduced to 5 per cent and 10 per 

 cent." 



