On average, 1 in 400 microchips made at a certain factory are faulty. The number of faulty microchips in a random sample of 1000 is denoted by $$$X$$$. Use this approximating distribution to find each of the following. $$$\mathrm{P}(X=4)$$$. ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................

Mathematics

IGCSE&ALevel

CAIE

Exam No：9709_m21_qp_62 Year：2021 Question No：4(c)(i)

Answer:

$e^{-2.5} \times \frac{2.5^{4}}{4 !}$
$0.134(3 \mathrm{sf})$

6.1.1 use formulae to calculate probabilities for the distribution $\text { Po }(\lambda)$