DIALING HABITS OF TKLEPHONE CUSTOMERS 



63 



during a particular 0.1 second interval are omitted from the number of 

 cases waiting for dial tone at the start of the next interval. 



In the development of the generalized trunking formula, the assump- 

 tion was made that the waiting times of calls infinitely delayed have an 

 exponential distribution. By assuming that the plots for the survivor 

 curves in the development comparable to the j factor analysis are ex- 

 ponential distributions, it is possible by reading the value of t correspond- 

 ing to 36.8 per cent of the subscribers still waiting for dial tone to obtain 

 estimates of the values of H for the six types of subscribers. These esti- 

 mates, most of which were obtained by extrapolation, are compared in 



100 



-COMPUTED DATA COMPARABLE TO j FACTOR ANALYSIS DATA 

 -COMPUTED DATA COMPARABLE TO SENDER MONITORING CIRCUIT DATA 



I 100 



o 



2 4 6 8 10 12 14 16 18 20 



TIME, t, IN SECONDS TO FIRST ACTION TAKEN BY A SUBSCRIBER 



FROM RECEIVER OFF HOOK 



Fig. 18 — Subscriber dialing habits based on individual line records when dial 

 tone is delayed indefinitely. 



