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CUET · MATHS · PYQ PAPER 2025

If the random variable \(X\) follows the Poisson distribution such that \(P(X=k)=P(X=k+1)\), then the mean value of \(X\) is :

  1. A \(k\)
  2. B \(k-1\)
  3. C \(k^2\)
  4. D \(k+1\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(k+1\)

Step-by-step Solution

Detailed explanation

\(\frac{e^{-\lambda} \lambda^k}{k!} = \frac{e^{-\lambda} \lambda^{k+1}}{(k+1)!}\) \(\frac{1}{k!} = \frac{\lambda}{(k+1)k!}\) \(1 = \frac{\lambda}{k+1}\) \(\lambda = k+1\)