Find the mean of the Binomial distribution $B\left(4, \frac{1}{3}\right)$.

The probability of getting $4$ heads in $8$ throws of a coin is:

For a binomial variate $X$ with $n=6$,if $P(X=2)=9 P(X=4)$,then its variance is

The probability that a missile hits a target successfully is $0.75$. In order to destroy the target completely,at least three successful hits are required. Then the minimum number of missiles that have to be fired so that the probability of completely destroying the target is $NOT$ less than $0.95$,is. . . . .

Four fair dice are thrown independently $27$ times. Then the expected number of times,at least two dice show up a three or a five,is

Suppose $X$ follows a binomial distribution with parameters $n$ and $p$,where $0 < p < 1$. If $\frac{P(X=r)}{P(X=n-r)}$ is independent of $n$ for every $r$,then $p$ is equal to