If $X \sim B(4, p)$ and $P(X=0)=\frac{16}{81}$,then $P(X=4)=$

$A$ bag consists of $10$ balls each marked with one of the digits $0$ to $9$. If four balls are drawn successively with replacement from the bag,what is the probability that none is marked with the digit $0$?

From a lot of $30$ bulbs which include $6$ defectives,a sample of $4$ bulbs is drawn at random with replacement. Find the probability distribution of the number of defective bulbs.

What is the probability of getting at least $1$ tail when a coin is tossed $4$ times?

An experiment succeeds twice as often as it fails. Then the probability,that in the next $6$ trials there will be at least $4$ successes,is

$A$ radar system can detect an enemy plane in one out of $10$ consecutive scans. The probability that it cannot detect an enemy plane at least two times in four consecutive scans is: