Question 1206368
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A telemarketer makes six phone calls per hour and is able to make a sale 
on 30% of these contacts. During the next two hours. Find: 
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Assuming that the next 2 hours he/she works at the same intensity 
(does not have a coffee break/(lunch break) and continues his working hours),
in the next two hours, he/she makes 12 phone calls.


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a) The probability of exactly making four sales 

   Ans: 12C4*0.3^4*0.7^(12-4) = 495*0.3^4*0.7^8 = 0.2311 (rounded).



b) The probability of making no sales.
   Ans: 0.7^12 = 0.01384 (rounded).



c) The probability of exactly making two sales.
   Ans: 12C2*0.3^2*0.7^(12-2) = 66*0.3^2*0.7^10 = 0.1678  (rounded).



d) The mean number of sales within the two-hour period.
   mean = np = 12*0.3 = 3.6 sales
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Solved.