Question

Assume 20% of people have a flu immunisation at the start of winter . Suppose that 5% of people who have a flu immunisation will contract the flu and that 30% of those who don’t have a flu immunisation will contract the flu

What proportion of people will contract the flu ?

Answer 1

Construct the following tree diagram for the given data :

Hence the proportion of people contracting the flu =(0.2*0.05)+(0.8*0.3)

=0.01+0.24

=0.25 or 25%