P(X=x)=(e-λ *λ x)/x!
λ =0.5
P(X=1)=(e-0.5*(0.5)0)/0!=0.60653
P(X=1)=(e-0.5*(0.5)1)/1!=0.30327
P(X=2)=(e-0.5*(0.5)2)/2!=0.07582
P(X>2)=1-P(X=0)-P(X=1)-P(X=2)=0.01439
(a) E(X)=50000*0.30327+100000*0.07582+200000*0.01439=25623.50
(b) E(X2)=500002*0.30327+1000002*0.07582+2000002*0.01439=2091975000
VAR(X)="\\sigma"2=E(X2)-(E(X))2=2091975000-(25623.50)2=1435411247.75
σ="\\sqrt{\\sigma^2}" =37886.82
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