272 



J. ARTHUR HARRIS 



Of the 14 negative values, only 6 are numerically higher than 

 r = —0.10. Of the 36 positive correlations, 16 are higher than 

 that value. When the number of observations is not very 

 large, little significance is to be attached to a correlation of only 

 r = ±0.10. Only two of the negative correlations fall farther 

 from 0 than r = — 0.19. Of the positive correlations, 6 fall in 

 the neighborhood of + 0.20 or higher. The mean of the 14 



:'?9°9oooo 



I : 1 r 1 90oo 



I N I r .1 I ; M M I . I990O. 



Fig. 1 Fig. 2 



Fig. 1. Values of correlation between weight and time required for germina- 

 tion. 



Fig. 2. Trustworthiness of correlations as measured by ratio to probable 

 error. 



negative correlations is r = — 0.089, that of the 36 positive deter- 

 minations r = +0.113. For the whole 50 cases, the mean is 

 r = + 0.057. 



These facts are shown graphically in diagram 1, where the 

 length of the bars represents the magnitude of the coefficients. 

 The circles and broken lines rising above the zero bar stand for 

 the positive values, while the solid dots and firm lines below the 

 zero bar indicate the negative. 



