If four dice are thrown simultaneously,then the probability that none of the dice shows the number $1$ on its face is:

For a binomial distribution,the mean and variance are $4$ and $2$ respectively. What is the probability of $X = 2$ (in $/256$)?

The probability that an event $A$ happens in a trial is $0.4$. If three independent trials are made,then the probability that $A$ happens at least once is

$A$ die is thrown $5$ times. If getting an odd number is considered a success,what is the variance of the probability distribution?

$A$ bag contains six balls of different colours. Two balls are drawn in succession with replacement. The probability that both the balls are of the same colour is $p$. Next,four balls are drawn in succession with replacement and the probability that exactly three balls are of the same colour is $q$. If $p : q = m : n$,where $m$ and $n$ are coprime,then $m + n$ is equal to $..........$.

Given that the probability of a man hitting a target with a gun is $\frac{1}{3}$. If he fires $8$ times,then the probability of his hitting the target at least twice is