Answer:
a) 0.905 (3 dp)
Explanation:
Binomial distribution X ~ B(n, p)
where n is the the number of trials and p is the probability of success
Binomial formula:
![P(X=x)=\left(\left\begin{array}{cc}n\\x\end{array}\right) \cdot p^x \cdot (1-p)^(n-x)](https://img.qammunity.org/2023/formulas/mathematics/high-school/ksfj7slzr2fusgcp68crpaemw07p7uymms.png)
Given: X ~ B(100, 0.001)
Therefore, n = 100 and p = 0.001
Substituting these values into the binomial formula and solving for x = 0:
![\implies P(X=0)=(100!)/(0!100!) \cdot 0.001^0 \cdot (1-0.001)^(100-0)](https://img.qammunity.org/2023/formulas/mathematics/high-school/wib26qc0d2wv0pek2avx283bi3pcji7k76.png)
![\implies P(X=0)=1 \cdot 1 \cdot 0.999^(100)](https://img.qammunity.org/2023/formulas/mathematics/high-school/je3oe7389lnjan911enweu0h9ermtk84ma.png)
![\implies P(X=0)=0.9047921471...](https://img.qammunity.org/2023/formulas/mathematics/high-school/b5znrzpyxesqsgnrdq47008qwre07bduof.png)
![\implies P(X=0)=0.905 \ \sf(3 \ dp)](https://img.qammunity.org/2023/formulas/mathematics/high-school/w40vtir83xmjat8w29snk0lcv406f3t5pf.png)