PREHARVEST APPLE DROP 



11 



Table 8. Correlation Between Yield and Per Cent Drop 



Variety 



Block 



Year 



Number 

 of trees 



Average Yield 

 (lbs.) 



Mcintosh 



26 



1935 

 1936 

 1937 

 1938 

 1939 

 1940 

 1941 



-.044 

 .078 

 .301 

 .346* 

 .143 

 494** 



.'338* 



31 

 29 

 33 

 35 

 38 

 37 

 35 



154.5 

 153.3 

 166.8 

 156.2 

 379.1 

 279 2 

 566.4 



Mcintosh 



BFP 



1932 

 1933 

 1934 

 1935 

 1936 

 1937 



.066 



.226 



.038 



.337** 



.020 



.100 



49 

 58 

 51 

 60 

 59 

 61 



47.4 

 702.0 

 103.2 

 480.3 

 136.7 

 404.8 



Mcintosh 



BF 



1935 

 1936 

 1937 

 1938 

 1939 

 1940 

 1941 



.380** 



.000 



.355** 



.271* 



,442** 



.383** 



.067 



64 

 68 

 71 

 71 

 87 

 88 

 90 



308.1 

 119.3 

 538.7 

 119.9 

 461.3 

 490.0 

 491.3 



Northern Spy BFP 



1935 

 1936 

 1937 

 1938 

 1939 

 1940 

 1941 



.407** 



.451** 



.192 



.405** 



.101 



.516** 



.501** 



60 

 57 

 60 

 50' 

 61 

 52 

 59 



416.6 

 398.0 

 485.4 

 199.7 

 820.1 

 192.8 

 488.6 



Starking 



26 



1938 

 1939 

 1940 

 1941 



.607** 



.000 



.000 

 -.509* 



25 

 31 

 30 

 14 



73.9 

 180.9 

 197.9 



70.2 



Delicious 



BF 



1935 

 1936 

 1937 

 1938 

 1939 

 1940 

 1941 



.090 

 -.083 

 .122 

 . 499** 



■.119 



.080 



-.241 



40 

 36 

 40 

 39 

 43 

 38 

 38 



Baldwin 



26 



Significant 



1940 



.666** 



42 



Highly Significant 



210.0 



The writer realizes that the correlation coefficient is of value on- 

 ly in indicating whether a change in the value of one factor is ac- 

 companied by a change in another factor, but cannot be used like re- 

 gression to show the magnitude of the change, since, as stated by 

 Snedecor^"*, "the correlation is the regression freed of differences in 

 units and in magnitude of variation." 



The value of the correlation coefficient does not give information 

 on the real eft'ect of yield on drop unless the magnitude of change in 

 per cent drop with change in yield is also taken into consideration. 

 Likewise, the correlation coefficient for the relation between weight 



