Answer
a)See below. b)There is sufficient evidence to support that the rate of polio is less for children given the vaccine.
Work Step by Step
a) The null hypothesis says $p_{1}=p_{2}$, whilst the alternative hypothesis says $p_{1} \lt p_2$.
b) Since $p \lt 0.001$, p is less than any significance level, hence the null hypothesis is rejected. Hence there is sufficient evidence to support that the rate of polio is less for children given the vaccine.
