STA301_LEC29

And since we are interested in 3 or more calls in a 15-second interval, therefore P(X > 3) = 1 - P(X < 3) = 1 - [P(X=0)+P(X=1)+P(X=2)] 2 e −(1)x =1 −∑ x =0 x !

2

(0.3679)(1)

= 1 −∑ x =0

x

x!

-1

(∴ e = 0.3679)

= 1 – (0.91975) = 0.08025