POISSON'S PROBABIIJTY SUMMATION 



623 



c4 Calls from group of four 

 coin-box telephones 

 total =384 

 average =2. 74 



c5 Calls from group of two 

 coin-box telephones 

 total = 212 

 average = 1 . 50 



c6 Calls from group of six 

 coin-box telephones 

 total =468 

 average =3. 39 



c7 Cutoffs 

 total =557 

 average =2. 09 



c8 Double connections 

 total =906 

 average =3. 39 



c9 Calls for wrong number 

 total = 1351 

 average =5. 06 



clO Connections to wrong 

 number 



total =2334 

 average =8. 74 



cl 1 Party lines 

 total = 1981 

 average =6. 60 



cl2 "Lost and found" 

 advertisements** 

 total = 7051 

 average =33. 7 



dl Number 12 

 total =421 

 average =4. 21 



