SEA-FISHERIES LABORATORY. 



Example: Table V, June, 1908-1913. 



125 



(1) 



(2) 



(3) 



(4) 



(5) 



(6) 



Mean 













length. 



/ 



/°/o 



■"J / oo 



y 



zy 



13-5 



1 



0-5 



1000-2 







14-5 



12 



6-4 



999-7 



"21 



99*8-8 



15-5 



39 



20-7 



993-3 



21-6 



996-7 



16-5 



106 



56-2 



9726 



64-4 



9751 



17-5 



205 



108-8 



916 4 



111-9 



910-7 



18-5 



304 



161-3 



807-6 



143-0 



798-8 



195 



263 



139-5 



646-3 



149-9 



655-8 



20-5 



231 



122-6 



506-8 



136-7 



505-9 



21-5 



228 



1210 



384-2 



112-6 



367-2 



22-5 



183 



971 



263-2 



85-7 



256-6 



23-5 



124 



65-8 



1661 



61-3 



170-9 



24-5 



67 



35-5 



100-3 



41-6 



109-6 



255 



45 



23-9 



64-8 



27-1 



68-0 



26-5 



24 



12-7 



40-9 



17-0 



40-9 



27-5 



20 



106 



28-2 



10-4 



23-9 



28-5 



9 



4-8 



17-6 



6-2 



13-5 



29-5 



14 



7-4 



12-8 



3-6 



7-3 



30-5 



5 



2-7 



5-4 



20 



3-7 



31-5 



3 



1-6 



2-7 



11 



1-7 



32-5 



2 



11 



11 



0-6 



0-6 





1,885 



1000-2 





998-8 





The plaice have been grouped into one cm. classes, 13 to 

 14, 14 to 15, and so on : Col. (1) gives the middle points of these 

 class-ranges ; Col. (2) gives the actual numbers of fish measured 

 and belonging to each class-range, and Col. (3) gives these 

 frequencies expressed as numbers per 1,000. Thus all the 

 series given in this report can be graphed on the same scale, 

 and the graphs can be superposed for comparison. But the 

 actually-observed frequencies are necessary whenever we 

 require to find the " probable errors," so they must be stated. 

 Col. (4), " 2/°/oo>" gives the results of the process of summa- 

 tion : thus the entry, 17-6, opposite the length, 28-5 cms., is 

 the sum, 4*8 + 74 + 2-7 -f 1-6 + 1-1, of the frequencies 

 opposite 17'G and below the latter. In this case the summation 

 begins at the bottom of the column, but it might as well 

 begin at the top. The entries in Col. (4) are to be read in this 



