Take these values as estimates, not facts.
There are also several factors, like all kinds of movement (note that movement attracts infected individually) and fighting noise, that will increase 'Aggro' (Aggression), or more exactly, the number of infected that may spawn nearby.
The health points of all infected stated here is only at the best accuracy from the actual health value. As you move into the higher level areas, however, progressively tougher infected will appear, some easily identifiable by their unique, mutated body types, and others may sprint at you enraged when you least expect it. When you first venture into the city, infected appear infrequently and are easy to kill.
