The mean and variance of a binomial distribution are $6$ and $4$. The parameter $n$ is

$A$ fair coin is tossed $n$ times. If the probability that head occurs $6$ times is equal to the probability that head occurs $8$ times,then $n$ is equal to:

If two coins are tossed $5$ times,then the probability of getting $5$ heads and $5$ tails 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. . . . .

For Binomial distribution $B \left(10, \frac{1}{2} \right)$,if $P(X \leq 2) = m \left( \frac{1}{2} \right)^{10}$,then $m =$ . . . . . . .

Five cards are drawn successively with replacement from a well-shuffled deck of $52$ cards. What is the probability that only $3$ cards are spades?