Question

Find the probability distribution of number of heads in two tosses of a coin,

Answer 1

Let X denote the number of heads.
Sample space of the experiment is
S = {HH, HT, TH, TT}
The values of X corresponding to these outcomes are as follows.
X(HH) = 2
X(HT) = X(TH) = 1
X(TT) = 0
∴ X is a discrete random variable that can take values 0, 1, 2.
The probability distribution of X is then obtained as follows:

X	0	1	2
P(X = x)	`(1)/(4)`	`(2)/(4)`	`(1)/(4)`