1) In a binomial distribution , mean is 18 and variance is 12 then p= A) 23 B) 13 C) 34 D) 12 Answer: Option BExplanation: We know that , mean =np=18 and variance = n p q =12 Now, mpqnp=1218⇒q=23 ∴ p=1−q=1−23=13