Two percent of the bolts manufactured in a factory are found to be defective. Using the Poisson distribution, the probability that in a sample of 100 bolts chosen at random, exactly two will be defective, is: [Given $e^{-2}=0.135$] |
0.5 1 0.135 0.27 |
0.27 |
The correct answer is Option (4) → 0.27 ** Defective rate = $2\% = 0.02$ Sample size = $100$ For Poisson approximation: $\lambda = np = 100 \times 0.02 = 2$ Probability of exactly 2 defectives: $P(X=2)=\frac{e^{-2}\,2^{2}}{2!}$ Given: $e^{-2}=0.135$ $P(X=2)=\frac{0.135 \times 4}{2}$ $P(X=2)=0.135 \times 2$ $P(X=2)=0.27$ Final Answer: $0.27$ |