Answer
$P(under 1)=\frac{1}{24}\approx0.042$
It is an unusual event.
Work Step by Step
The sample space is the caseload. So, N(S) = 24
There is 1 case involving children under 1 year old. So, N(under 1) = 1.
$P(under 1)=\frac{N(under 1)}{N(S)}=\frac{1}{24}\approx0.042$
0.042 $\lt$ 0.05. So, it is an unusual event.
