afford — Tougan Place Names 21 



Table 5 is based on the same principle as Table 4, but the total of 

 names in each group is taken as the basis instead of shared names. Like 

 Table 4, Table 5 should be read downward, the name at the head of each 

 column being that of the group under consideration. Thus, Vavau has 

 29 per cent of all its names in common with Tongatabu, but Tongatabu 

 has only 19 per cent of its names in common with Vavau. 



TABLE 5. — PERCEXT,\GE OF NAMES COMMON TO EACH TWO GROUPS ON B.\SIS 

 OF TOTAL, NAMES OF EACH GROUP 



Tongatabu Haapai Vavau Niuafoou Niuatoputapu 



Tongatabu 26 29 2g 30 



Haapai 18 11 2i 27 



Vavau ig 10 23 32 



Niuafoou 556 14 



Niuatoputapu 2346 



Table 6 presents the average percentage indexes of the interrelations of 

 the island groups. The upper diagonal half of the table employs the per- 

 centages presented in Table 4 based on shared names only. The lowei 

 diagonal half of the table employs the percentages presented in table 5 

 based on all names in each group. The so-called average percentage index 

 is the average of the two percentages of relationship for each two groups. 

 Thus, in Table 4, Tongatabu has 60 per cent of its shared names in com- 

 mon with Haapai ; Haapai has 78 per cent of its shared names in common 

 with Tongatabu ; the average percentage index for the two groups, based 

 on shared names, is therefore 60 plus 78, divided by 2, or 6g, which is 

 the figure entered in Table 6. It would appear that the average percentage 

 indexes based on all names in each group express more nearly the relation 

 which subsists between each two groups than do the percentage indexes 

 based on shared names, since the percentage of shared names varies in 

 each group (see Table 2), whereas the percentage of total names in each 

 group is always 100. 



TABLE 6. — AVERAGE PERCENTAGE INDEXES OF INTERREL.KTIONS OF ISLAND 



GROUPS 



Tongatabu Haapai Vavau Niuafoou Niuatoputapu 



^ — — ___^^^ BASED ON SHARED NAMES 



Tongatabu ....ZiT^--^^^ 69 70 45 36.S 



Haapai 22 — ~~-— ~-_^° ^^ ^^ 



Vavau 24 10.5 ^ — ^^^^ 37 385 



Niuafoou 17 13 14.S ^~~^ — --_^^ 22.5 



Niuatoputapu 16 15 18 k 



BASED ON ALL NAMES 



Whether we base the indexes of group interrelations upon the per- 

 centage of shared names or upon the percentage of all names, certain 

 significant breaks in our series of figures appear. 



