ISRO | ISRO CS 2009 | Question 78

If the pdf of a Poisson distribution is given by f(x) = (e^-22^x)/x!, then its mean is
(A) 2^x
(B) 2
(C) -2
(D) 1

Answer: (B)
Explanation: f(x) = (e^-22^x)/x!
In the poison distribution expression,
e^-λ λ^k)/k!
here, k = number of events
λ = expected value/ average/ mean over ‘k’ number of values

So, mean = 2, option (B) is correct.

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