If $P(X=2)=0.3, P(X=3)=0.4, P(X=4)=0.3$,then the variance of random variable $X$ is (in $.6$)

The value of $C$ for which $P(X = k) = Ck^2$ can serve as the probability function of a random variable $X$ that takes values $0, 1, 2, 3, 4$ is

Let $X$ represent the difference between the number of heads and the number of tails obtained when a coin is tossed $6$ times. What are the possible values of $X$?

The cumulative distribution function of a continuous random variable $X$ is given by $F(x) = \frac{\sqrt{x}}{2}$ for $0 \leq x \leq 4$. Then $P[X > 1]$ is

If the range of a random variable $X$ is $\{0, 1, 2, 3, 4, \ldots\}$ with $P(X=k) = \frac{(k+1)a}{3^k}$ for $k \geq 0$,then $a$ is equal to

$A$ coin is tossed until one head appears or a tail appears $4$ times in succession. The probability distribution of the number of tosses $X$ is: