Probability Question 146
Question: In a book of 500 pages, it is found that there are 250 typing errors. Assume that Poisson law holds for the number of errors per page. Then, the probability that a random sample of 2 pages will contain no error, is
Options:
A) $ {e^{-0.3}} $
B) $ {e^{-0.5}} $
C) $ {e^{-1}} $
D) $ {e^{-2}} $
Show Answer
Answer:
Correct Answer: C
Solution:
Here number of erros per page $ =\frac{250}{500}=\frac{1}{2} $
And $ n=2\therefore \lambda =np=2\times \frac{1}{2}=1 $
And probability of no error $ P(X=0)=\frac{{e^{-1}}\times {{(1)}^{0}}}{0!}={e^{-1}} $
BETA
