In a binomial distribution,the mean is $18$ and the variance is $12$,then $p = . . . . . .$

If the probabilities of a boy and a girl being born are the same,then in a $4$-children family,the probability of having at least one girl is:

$A$ die is thrown $100$ times. If the success is defined as getting an even number,then the variance of the number of successes is:

An unbiased coin is tossed to get $2$ points for turning up a head and $1$ point for the tail. If three unbiased coins are tossed simultaneously, then the probability of getting a total of an odd number of points is

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

$A$ 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: