An experiment succeeds twice as often as it fails. Find the probability that in the next six trials, there will be at least 4 successes.
It is given in the question that,
Probability of failure = x
And, probability of success = 2x
∴ x + 2x = 1
3x = 1
∴
Let us now assume
Also, X be the random variable that represents the number of trials
Hence, by binomial distribution we have:
∴ Probability of having at least 4 successes
= P (X = 4) + P (X = 5) + P (X = 6)