Question

Find the probability distribution of X, the number of heads in a simultaneous toss of two coins.

Answer 1

Possible values of X are 0, 1, or 2 

Now P(X = 0) = P(No head) 

= P(Tail first time and tail second time) 

= P(Tail first time).P(Tail in second time) 

= 1/2 × 1/2 = 1/4 

= P(TH or HT) = P (TH) + P(HT) 

= 1/4 + 1/4 = 1/2

P(x = 2) = P (2 Head) = P(HH) = 1/4

∴ Required distribution is