Practicing Success
A bag contains four tickets marked with numbers 112, 121, 211, 222. One ticket is drawn at random from the bag. Let Ei (i = 1, 2, 3) denote the event that ith digit on the selected ticket is 2, then which of the following is not correct ? |
E1 and E2 are independent E2 and E3 are independent E3 and E1 are independent E1, E2 and E3 are independent |
E1, E2 and E3 are independent |
$P\left(E_1\right)=\frac{2}{4}=\frac{1}{2}, P\left(E_2\right)=\frac{2}{4}=\frac{1}{2}, P\left(E_3\right)=\frac{2}{4}=\frac{1}{2}$ $P\left(E_1 \cap E_2\right)=\frac{1}{4}=P\left(E_1\right) .\left(E_2\right)$ $\Rightarrow$ '$E_1$' and '$E_2$' are independent. $P\left(E_1 \cap E_3\right)=\frac{1}{4}=P\left(E_1\right) .\left(E_3\right)$ $\Rightarrow$ '$E_1$' and '$E_3$' are independent. $P\left(E_2 \cap E_3\right)=\frac{1}{4}=P\left(E_2\right) .\left(E_3\right)$ $\Rightarrow$ '$E_2$' and '$E_3$' are independent. $P\left(E_1 \cap E_2 \cap E_3\right)=\frac{1}{4} \neq P\left(E_1\right) . P\left(E_2\right) .\left(E_3\right)$ $\Rightarrow E_1, E_2$ and $E_3$ are not independent. |