i was doing some exercises nut i'm not sure if my answers are correct(adsbygoogle = window.adsbygoogle || []).push({});

1) X~B(5,0.25) i have to find:

a) E(x^2) and my answer was 2.5, is this correct?

b) P(x(>or=to)4) and my answer was 0.0889, is this correct?

2) X~Geom(1/3) i have to find:

a) E(x) my answer is 1/3

b) E(x^2)

c) var(x)

d) P(X=4) my answer is 0.988

e) P(X>2) my answer is..... -(1/18)

i dont know how to compute b) and c)

and i think d) is wrong

and i know e) is wrong.

can someone help please.

Thank you very much

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# Binomial and geometric distributions

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