372 THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1953 



0.1 

 8 



5 00' 



< s 



O 6 



a. 



0.001 

 8 



0.0001 



t/h= DELAY IN MULTIPLES OF AVERAGE HOLDING TIME 



Fig. 10 — Delayed traffic served in random order, exponential holding times 

 c = 3. ' 



as abscissa, and P{>t/h), the probability of a random call meeting a 

 delay greater than t/h, as ordinate. 



Estimates of average delays, t (which are the same for queued and 

 random service), are also commonly desired, and these are shown in 

 Fig. 19. They are calculated from the equation 



t/h = P(>0)/(c - a) 



(2) 



If one wishes instead the average delay, t, on calls delayed, it may be 

 obtained from 



't/h = 



t/h 



1 



P(>0) c 



(3) 



