If $15 \%$ of the members of a population affected by a disease $8 \%$ died, the mortality rate in relation to the entire population is:
(a) $1.2 \%$
(b) $1.8 \%$
(c) $8 \%$
(d) $12 \%$
(e) $23 \%$
The proportion of the population that falls ill due to the disease is $\frac{15}{100}$, and of those who fall ill, the proportion that dies is $\frac{8}{100}$. Therefore, the proportion of the population that dies from the disease is $\frac{15}{100} \times \frac{8}{100}$, which corresponds to

$$
\frac{15 \times 8}{100^{2}}=\frac{120}{10000}=\frac{12}{1000}=\frac{1.2}{100}=1.2 \%
$$

The correct option is (a).