Question

A weighted coin P(H)=2/3,P(T)=1/3 , is tossed three times.
If the variate X denotes the number of heads produced in three
tosses, find
(i) the p.m.f. of X
(ii) the c.d.f. of X
(iii) P [X = 2].

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Answer 1

1/2 x 1/2 x 1/2 = 1/8. The probability of getting a head on a fair coin is 1/2, and because you want 3 of these, you multiply by 1/2 3 times.