144 



A slight interpolation in our tables will thus yield thèse 

 quantities. 



If we wish to take them out of our figures we hâve 

 to consider that 

 to value 0.25 in scheme corresp. the value z = — 0.4769 . . 



.. „ 0.50 „ z= 0.0000.. 



.. .. 0.75 „ „ „ „ „ z= +0.4769.. 



Therefore the values xo.25. y. •Xojs will be the x for 

 which z is resp. — 0.4769 . . ., 0.0000 ... and + 0.4769 . . 

 In the figures the horizontal lines representing thèse values 

 hâve been.drawn slightly heavier than the rest. For the 

 points of intersection of the z line with thèse heavier lines 

 we hâve thus to read off the abscissae. They are at once 

 the values of Aro.25, [J- and xo.75 and we hâve the médian 

 and quartiles by (e). 



