Question 1012442
Use Poisson distribution with lambda=2.5
exp(-2.5)*2.5^0/0!
That is exp(-2.5)=0.082 for 0 calls
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for 1 call
exp(-2.5)*2.5/1=0.205
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At least 1 call arrives is 1-P(0 call arrives)=0.918
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That is 2 calls in a Poisson distribution of lambda=1.25
exp(-1.25)*1.25^2/2
=0.224