Final answer:
External validity refers to generalizing the findings of a study, while internal validity refers to accurate measurement and controlling confounding variables.
Step-by-step explanation:
External validity refers to the extent to which the findings of a study can be generalized to other populations, settings, and conditions. It prompts researchers to ask questions such as: Does the study sample represent the larger population? Is the study conducted in a natural setting? On the other hand, internal validity refers to the extent to which the study accurately measures what it intends to measure. It prompts researchers to ask questions such as: Did the study control for confounding variables? Was the study design appropriate for testing the hypothesis?