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NDA 2026
Exam
NDA
Year
2026
Subject
Mathematics
Chapter
Probability

NDA 2026 · Mathematics · Probability

For a Binomial distribution with mean 6 and standard deviation 2 ,...

For a Binomial distribution with mean 66 and standard deviation 2,whatisthevalueof\sqrt{2}, what is the value ofP(X=0)??

Options

  1. A(13)9\left(\dfrac{1}{3}\right)^9
  2. B(23)9\left(\dfrac{2}{3}\right)^9
  3. C13(23)8\dfrac{1}{3}\left(\dfrac{2}{3}\right)^8
  4. D23(13)8\dfrac{2}{3}\left(\dfrac{1}{3}\right)^8

Correct answer

A. (13)9\left(\dfrac{1}{3}\right)^9

Step-by-step solution

Let nn be the number of trials and pp be the probability of success.

Mean =np=6= np = 6

Standard deviation =npq=2= \sqrt{npq} = \sqrt{2}

Variance =npq=2= npq = 2

Dividing the variance by the mean:

npqnp=26\dfrac{npq}{np} = \dfrac{2}{6}

q=13q = \dfrac{1}{3}

Since p+q=1p + q = 1, we get p=23p = \dfrac{2}{3}.

Substituting pp into the mean equation:

n(23)=6⇒n=9n\left(\dfrac{2}{3}\right) = 6 \Rightarrow n = 9

The probability of X=0X = 0 is given by:

P(X=0)=nC0p0qnP(X=0) = ^{n}C_{0} p^0 q^n

P(X=0)=9C0(23)0(13)9=(13)9P(X=0) = ^{9}C_{0} \left(\dfrac{2}{3}\right)^0 \left(\dfrac{1}{3}\right)^9 = \left(\dfrac{1}{3}\right)^9

Answer: \left(\dfrac{1}{3}\right)^9
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