$A$ die is thrown $5$ times. If getting an odd number is considered a success,what is the variance of the probability distribution?

$A$ multiple choice examination has $5$ questions. Each question has three alternative answers of which exactly one is correct. The probability that a student will get $4$ or more correct answers just by guessing is:

Find the probability of getting $5$ exactly twice in $7$ throws of a die.

The mean and standard deviation of a binomial variate $X$ are $4$ and $\sqrt{3}$ respectively. Then $P(X \geq 1)$ is equal to

The probability that a student is not a swimmer is $\frac{1}{5}$. Then,the probability that out of $5$ students,$4$ are swimmers is . . . . . . .

The probability that $A$ wakes up before the alarm rings is $0.4$. Then,the mean and variance of the number of times $A$ wakes up before the alarm rings,in the next $7$ days respectively are: