0
943views
Find the M.G.F. of Poisson Distribution.

Hence find its variance and mean.

1 Answer
0
9views

Solution:

i) Moment Generating Function (M.G.F.)

The M.G.F. about the origin is:

M0(t)=E(etx)=p(x)etx=x=0emmxx!.etx=emx=0(met)xx!=em.emet

M0(t)=em(et1)

ii) Mean and Variance of Poisson Distribution

μ1=E(x)=pixi=x=0emmxx!x=x=1emmx(x1)!=memx=1m(x1)(x1)!

μ1=mem[1+m+m22!+m33!+]=mem.em=m

Mean =μ1=m

μ2=E(x2)=pix2i=x=0em.mxx!x2

x2=x+x(x1)

μ2=x=0em.mxx![x+x(x1)]=x=0em.mx.xx!+x=0em.mx.x(x1)x!

μ2=memx=1mx1(x1)!+m2emx=2mx2(x2)!

μ2=mem.em+m2em[1+m1!+m22!+]

μ2=mem.em+m2em.em=m+m2

μ2=μ2μ1=m+m2m2=m

Variance=μ2=m

Please log in to add an answer.