CAIE S2 2020 June — Question 5

Exam BoardCAIE
ModuleS2 (Statistics 2)
Year2020
SessionJune
PaperDownload PDF ↗
TopicPoisson Distribution

5
  1. The random variable \(X\) has the distribution \(\operatorname { Po } ( \lambda )\).
    1. State the values that \(X\) can take.
      It is given that \(\mathrm { P } ( X = 1 ) = 3 \times \mathrm { P } ( X = 0 )\).
    2. Find \(\lambda\).
    3. Find \(\mathrm { P } ( 4 \leqslant X \leqslant 6 )\).
  2. The random variable \(Y\) has the distribution \(\operatorname { Po } ( \mu )\) where \(\mu\) is large. Using a suitable approximating distribution, it is found that \(\mathrm { P } ( Y < 46 ) = 0.0668\), correct to 4 decimal places. Find \(\mu\).

5 (a) The random variable $X$ has the distribution $\operatorname { Po } ( \lambda )$.\\
(i) State the values that $X$ can take.\\

It is given that $\mathrm { P } ( X = 1 ) = 3 \times \mathrm { P } ( X = 0 )$.\\
(ii) Find $\lambda$.\\

(iii) Find $\mathrm { P } ( 4 \leqslant X \leqslant 6 )$.\\

(b) The random variable $Y$ has the distribution $\operatorname { Po } ( \mu )$ where $\mu$ is large. Using a suitable approximating distribution, it is found that $\mathrm { P } ( Y < 46 ) = 0.0668$, correct to 4 decimal places.

Find $\mu$.\\

\hfill \mbox{\textit{CAIE S2 2020 Q5}}