The number of typographical errors in a document follows a Poisson distribution with a mean of 2 errors per page. Let X represent the number of errors on 4 pages. Find P(5).
A) 0.1221
B) 0.0916
C) 0.9639
D) 0.0361

Question

Quizplus · Accepted Answer

Since the number of errors on a page follows a Poisson distribution with mean $\lambda=2$, the number of errors on 4 pages also follows a Poisson distribution with mean $\lambda=8$. Thus, $X \sim 	ext{Poisson}(\lambda=8)$.

To find $P(5)$, we can use the Poisson probability mass function:

$$P(X=5) = \frac{e^{-8}8^5}{5!} \approx 0.0916$$

Therefore, the best choice is B.

The Number of Typographical Errors in a Document Follows a Poisson