a) An insurance company attends 50 clients a day. On average 3 in 100 require special services. On a certain day it is found that there are 3 special service providers available. Assuming that 50 clients will be attended to, find the probability that there are more than three clients require special services?
The appropriate distribution for this question is Poisson distribution.
"P(X=k) = \\frac{\u03bb^k \\times e^{-\u03bb}}{k!} \\\\\n\nP(X>3) = 1 -P(X\u22643) \\\\\n\n= 1 \u2013 [P(X=0) + P(X=1) + P(X=2) + P(X=3)]"
Mean "\u03bb= \\frac{3}{2} = 1.5" (for 50 clients)
By Excel function
P(X≤3) = POISSON(3,1.5,1)
= 0.93435
P(X>3) = 1 -0.93435 = 0.06565
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