34 STATISTICAL METHODS. 



(arc of circle) = 5, 



n A /s e 

 2/o=y4/ oT- 



___ 



<j>= angle whose tangent is . 

 s 



To compare any observed frequency polygon 

 of Type V with its corresponding theoretical 

 curve. 



To find p solve the quadratic equation 

 and take the positive root. 



r =a(p -2)v / P z: 3; ?/o=rrLiv D==S ^^Y 



To compare any observed frequency polygon 

 of Type VI with its corresponding theoretical 

 curve. 



y=y (x-W 2 /* qi - 



1 q l and q 2 -{- 1 are the two roots of the equation 



l i =s i^-' <, where (1-qJ and s are negative; 



- 



D=; 



* The foregoing value is approximate and is applicable when, as is 

 usually the case, a is greater than 2. The exact value is given by 

 Pearson as 



/ > 



(sin 6fe T0 dd 

 . 



the formula for reducing which is to be gained from the integral cal- 

 culus. 



