62 



THE BELL SYSTEM TECHNICAL JOURNAL, JANUARY 1952 



COMPUTED DATA COMPARABLE TO j FACTOR ANALYSIS DATA 

 COMPUTED DATA COMPARABLE TO SENDER MONITORING CIRCUIT DATA 



+j 80 



2 4 6 8 10 12 14 16 18 2C 



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



FROM RECEIVER OFF HOOK 



Fig. 17 — Subscriber dialing habits based on individual line records when dia 

 tone is delayed indefinitely. 



that caused the sender to release were each counted as separate attempts. 

 The results arrived at are shown as survivor curves on Figs. 17(a) to 

 19(b) for each of the six types of subscribers studied. 



The survivor curves were developed by considering events during 

 0.1 second intervals. The number of cases of dialing before tone and 

 the number of cases of disconnection before tone occurring during a 

 O.I second interval were divided by the number of cases waiting for dial 

 tone at the start of the interval. This ratio was considered to be a 

 retirement rate. The complement of this rate gave a survival rate. By 

 a progressive multiplication of survival rates from time, t = 0, the 

 resulting survivor curves were obtained. Those cases receiving dial tone 



