158 Tables for Statisticians and Biometricians 



TABLE XVI. 



Standard Error of a Correlation Coefficient found from a Bi-serial Table*. 



The mean is given by : 



The bi-serial value of the correlation coefficient has the standard error 



whilst that of the product moment value* is 



In table XVI bis a comparison of the values of the numerator is made for five 

 values of r, for divisions at 0, '5, ... 2'5 times the standard deviation from the mean 

 of the ungraded character. 



TABLE XVI 6w. 



For large samples. 



