Question

Amit tosses a fair coin twice, and let $X$ be defined as the number of heads he observe. Find probability mass function $P_x$.

• A. $\frac{1}{3}$
• B. $\frac{1}{8}$
• C. $\frac{1}{4}$
• D. None off these

Answer 1

Answer: (C)

$\frac{1}{4}$

Given Amit tosses a fair coin twice

$\therefore$ Sample space, $S=[HH,HT,TH,TT]$

$\Rightarrow$ When $P\left(x\right)=1$ it is a PMF

i.e, $\frac{1}{4}+\frac{2}{4}+\frac{1}{4}=\frac{4}{4}=1$

$\therefore$ Probability mass function $Px=\frac{1}{4}.$

Hence, the answer is $\frac{1}{4}.$