RELIABILITY OF TRAFFIC MKASURFMIONTS 377 



2. For r < 1 



]\Iin. o-x = for r = 1, |, i, j, etc. 



Max. „, = ^i _ 1 = ,^ = ; ^ (18) 



for /• = |-, I, y, etc. 



Expressing this erroi- in terms of carried load and proceeding as in 

 Part ] of tlie Appendix 



I- '•> 1 V.= ^^]/^(r- 1) (19) 



2. /• < 1 :\IiiL 1' = 



Max. V. = 100 I ^/^ (20) 



^100 /:3:: 



c/T y 4a'NTt 



Equation (20) compares favoralily with the exponential holding time 

 coefficient of variation of error of 



c/T y Qa'NTi 



REFERENCES 



1. R. I. Wilkinson, "The RelialiilitN' of Holding Time Measurements," Bell Si/slem 



Tech. ./., 20, pp. 365-404, October, 1941 . 



2. J. Riordan, "Telephone Traffic Time Averages," Bell Si/stem Tech. J., 30, j^p. 



1129-1144, October, 1951. 

 .3. F. W. Rabe, "Variations of Telephone Traffic," Electrical Cointnunicalinns, 26, 



pp. 243-24S, 1948. 

 The following books contain descriptions of the use of generating functions in 

 solving probability problems: 



4. A. C. .\ilken. Statistical Mathematics, Oliver and Ho\-d, Ltd., Edinl)urgli, 1947, 



pp. 16-23. 



5. W. Feller, An Introduction to Probability Theori/ and Its Applications, John 



Wiley & Sons, Inc., New York, 1950, Chap. 11. 



