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If a random variable X follows binomial distribution with mean 43\dfrac{4}{3} and variance 89\dfrac{8}{9}. Which of the following are correct?

A. Probability of success is 13\dfrac{1}{3}.

B. Probability of failure is 23\dfrac{2}{3}.

C. Number of trials is 4.

D. P(X≥1)=3581P(X \ge 1) = \dfrac{35}{81}

Choose the correct answer from the options given below:

Solution

✅ Correct Option: 3

From npq/np=qnpq/np = q we get q=(8/9)/(4/3)=2/3q = (8/9)/(4/3) = 2/3, so p=1/3p = 1/3 and n=4n = 4; A, B and C hold.

But P(X≥1)=1−(2/3)4=1−16/81=65/81P(X\ge1) = 1 - (2/3)^4 = 1 - 16/81 = 65/81, not 35/8135/81, so D fails.

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