JEE Mains · Maths · STD 12 - 13. probability
If \(X\) has a binomial distribution, \(B( n, p)\) with parameters \(n\) and \(p\) such that \(P(X\, = 2)\, = P (X\, = 3)\), then \(E(X)\), the mean of variable \(X\), is
- A \(2 - p\)
- B \(3 - p\)
- C \(\frac{p}{2}\)
- D \(\frac{p}{3}\)
Answer & Solution
Correct Answer
(B) \(3 - p\)
Step-by-step Solution
Detailed explanation
since \(X\) has a binomial distribution, \(B(n,\) \(p)\) \(\therefore \mathrm{P}(X=2)=^{n} \mathrm{C}_{2}(p)^{2}(1-p)^{n-2}\) and \(P(X=3)=^{n} C_{3}(p)^{3}(1-p)^{n-3}\) Given \(\mathrm{P}(X=2)=\mathrm{P}(X=3)\)…
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