The variable I=f(w) represents the number of individuals (in thousands) infected w weeks after the epidemic begins.
The value of I=f(2) represents the number of individuals in thousandas infected 2 weeks after the beginning of the epidemic.
From the graph, where I=8, we can conclude that there are 8,000 infected people after 2 weeks of the beginning of the epidemic.
Answer:
f(2) = 8
Means 8,000 people are infected after 2 weeks of the beginning of the epidemic.