Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
A random variable $X$ has Poisson distribution with mean 2. Then $P(X>1.5)$ equals
MathematicsProbabilityJEE MainJEE Main 2005
Options:
  • A
    $\frac{2}{\mathrm{e}^2}$
  • B
    0
  • C
    $1-\frac{3}{\mathrm{e}^2}$
  • D
    $\frac{3}{\mathrm{e}^2}$
Solution:
2192 Upvotes Verified Answer
The correct answer is:
$1-\frac{3}{\mathrm{e}^2}$
$$
\begin{aligned}
& P(x=k)=e^{-\lambda} \frac{\lambda^k}{k !} \\
& P(x \geq 2)=1-P(x=0)-P(x=1) \\
& =1-e^{-\lambda}-e^{-\lambda}\left(\frac{\lambda}{1 !}\right) \\
& =1-\frac{3}{e^2} .
\end{aligned}
$$

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.