664 



MEMOIRS NATIONAL ACADEMY OF SCIENCES. 



Table 181. — Per cent distribution of grades, by form. 



[Vol. XV, 



i Total (or each form obtained by averaging per cents for each group, officers counting one-fifth. 



Examination of these tables shows that at the quartile and median points there is a fairly 

 constant difference of 6 or 6.5 points (raw score) between the extreme forms 5 and 6, form 5 

 being in all cases the easier. 



The figures, excluding Camp Dix to allow comparison of form 8 with the other forms, 

 show that this form is to be placed with 7 and 9. These three forms appear to be very nearly 

 equivalent, easier than form 6 and more difficult than form 5. The Hollerith sampling places 

 form 9 much closer to form 6, and shows small but significant difference between 7 and 8. 



It is interesting to observe that these differences in difficulty had remained similar even 

 through the revision of examination a to alpha. Reference to chapter 15, section 5, Part II, 

 will show that the evidence on examination a indicated that form A was significantly easier 

 than the others, while forms B and E seemed the most difficult. 



