In: Math
For a poisson distribution where X ~ Pois(u), solve the questions below. Please show all work and all steps.
a.) Show that the pmf is a pmf using the criteria for verifying pmf (2 conditions).
b.) Show that E(X) = u
c.) Show that Var(X) = u
Let , 
Therefore , the probability mass function of X is ,
; x=0,1,2,..........
= 0 ; otherwise
a) Now, we shall verify that P(X) is a probability mass function
(i)
;
for all x
(ii)





b)


; Since the term corresponding to x=0 is zero
; Since , 


c) The second raw moment is ,



; Since ,
;
Since the term corresponding to x=0 and x=1 are zero


Therefore ,