Final answer:
Katherine hesitates to talk to a stranger because she doesn't trust them.
Step-by-step explanation:
Katherine hesitates to talk to a stranger because she doesn't trust strangers. This is indicated by the fact that she skips four houses on her route because she is running late for an appointment and does not record the addresses or return later. Additionally, she fills in the forms by selecting random answers from other residents in the neighborhood. Her hesitation to talk to a stranger is based on a lack of trust and the potential risks associated with engaging with someone unfamiliar.