It is observed that $30 \%$ of the students appearing for a certain entrance test are science students. If $5$ students are randomly selected from this group,the probability of having $2$ science students among these students is

Two cards are drawn successively with replacement from a well-shuffled pack of $52$ cards. The mean of the number of kings is:

In a random experiment of throwing $5$ coins, the number of heads is defined as a random variable. The mean of the random variable is

Six balls are drawn successively from an urn containing $7$ red and $9$ black balls. Determine whether or not the trials of drawing balls are Bernoulli trials when after each draw,the ball drawn is replaced.

In a random experiment,two dice are thrown and the sum of the numbers appeared on them is recorded. This experiment is repeated $9$ times. If the probability that a sum of $6$ appears at least once is $P_1$ and a sum of $8$ appears at least once is $P_2$,then $P_1 : P_2 =$

For a binomial distribution with mean $6$ and variance $2$,find $P(X \geq 2)$.