Final answer:
Factors that contribute to the overestimation of stranger killings include the availability heuristic, media influence, and the universal tendency to be suspicious of strangers.
Step-by-step explanation:
The overestimation of stranger killings can be influenced by several factors. One factor is the availability heuristic, which is the tendency to judge the likelihood of an event based on how easily it comes to mind. In the case of stranger killings, stories of such crimes may be more vividly recalled and thus perceived as more common.
Another factor is the influence of media and popular culture, which often portrays crime in a sensationalized manner and can create a distorted perception of the crime rate. Furthermore, there is a universal tendency for humans to be suspicious of strangers, which can contribute to the overestimation of danger.