RELIABILITY OF TKAFFIC MKASUHKMKNTS 



367 



LOAD IN ERLANGS 

 2 4 6 8 (0 



800 

 600 



*{? 200 



100 

 80 



2 60 

 O 



LOAD IN HUNDRED-CALL-SECONDS PER HOUR 



Fig. 5 — Hours of measurement required for 90 per cent assurance that error in 

 estimating source load does not exceed plus or minus 5 per cent when measuring 

 interval is 300 seconds. 



6 8 10 20 40 60 100 200 400 1000 2000 4000 



LOAD IN HUNDRED-CALL-SECONDS PER HOUR 



10,000 



Fig. 6 — Limits of error reached with 90 per cent assurance in estimating source 

 load. 



