If $S$ be the sample space of a random experiment $\xi$ and $P$ be a probability function defined on the…
If $S$ be the sample space of a random experiment $\xi$ and $P$ be a probability function defined on the power set $P(S)$ of $\mathrm{S}$, then which one of the following is not satisfied by P?
(i) $\mathrm{P}(\phi)=0$
(ii) If $\mathrm{E}^{\mathrm{c}}$ is the complementary event of $\mathrm{E}$, then $\mathrm{P}\left(\mathrm{E}^{\mathrm{c}}\right)=$ $1-P(E)$
(iii) $0 \leq \mathrm{P}(\mathrm{E}) \leq 1, \forall \mathrm{E} \subseteq \mathrm{S}$
(iv) If $\mathrm{E}_1 \subseteq \mathrm{E}_2 \mathrm{P}\left(\mathrm{E}_2\right) \leq \mathrm{P}\left(\mathrm{E}_1\right)$
(iii)
(iv)
(ii)
(i)
Solution
If $E_1 \subseteq E_2$
Then $P\left(E_1\right) \leq P\left(E_2\right)$
$\therefore$ Statement (iv) is not satisfied by $P$