APPENDIX I 



209 



The wide scatter of the points showed that there was some factor at work 

 not included in the study. Part of the argument in favour of including the 

 curves here, instead of merely suppressing them as not significant, depended 

 on die realization that, if the wide scatter was due to some random error in 

 the measurement of migration, the regression would not be different, since 

 random errors in the dependent variable only alter the correlation. In spite of 

 the unsatisfactory scatter of the points, it is therefore quite possible that the 

 curves as drawn do represent the facts, overlaid by a random error. They 

 agree well with ordinary practical experience. 



(j) Contingency Tables for the Associations between the Weather 



AT the Spawn Date and Spawning 

 (a) Rainfall 



X^ — 7*5. P = less than o-oi 

 (b) Dry Days and Wet and Dry Nights 



3-72. P = 0-05 



[c) Temperature Above and Below io°C 



X^= 1-58. P= 0-2 



(d) Temperature Minimum Above and Below o°C 



^2 _ 0*003 . P = 0-9O-0-95 



14— (T.9I4) 



