The random variable $$$X$$$ has the distribution $$$\mathrm{B}(400,0.01)$$$. Use your approximating distribution to find $$$\mathrm{P}(2 \leqslant X \leqslant 5)$$$. ................................................................................................................................................ ................................................................................................................................................ ................................................................................................................................................ ................................................................................................................................................ ................................................................................................................................................ ................................................................................................................................................ ................................................................................................................................................ ................................................................................................................................................ ................................................................................................................................................

Mathematics

IGCSE&ALevel

CAIE

Exam No：9709_s21_qp_62 Year：2021 Question No：2(b)(ii)

Answer:

$\mathrm{e}^{-4}\left(\frac{4^{2}}{2 !}+\frac{4^{3}}{3 !}+\frac{4^{4}}{4 !}+\frac{4^{5}}{5 !}\right)$
$0.694(3 \mathrm{sf})$

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