Question

The probability that an individual suffers a bad reaction from an injection is 0.001. The probability that out 2000 individuals exactly three will suffer bad reaction is

• A. $\frac{1}{e^2}$
• B. $\frac{2}{3e^2}$
• C. $\frac{8}{3e^2}$
• D. $\frac{4}{3e^2}$

Answer 1

The correct option is D $\frac{4}{3e^2}$

# Given $P=0.001,n=2000$

$\lambda =nP=2$

$P(ϵ\times a+ly3)=P(x=3)$

$=\frac{e^{-\lambda }{\lambda }^x}{x!}=\frac{e^{-2}{2}^3}{3!}=\frac{4}{3e^2}$