Final answer:
Kerri was using the method of participant observation to study the effects on her family when her oldest brother went off to college.
Step-by-step explanation:
Kerri was using the technique called participant observation. This approach is when a researcher immerses herself in a group or social setting in order to make observations from an "insider" perspective. In the case of Kerri, she observed and recorded the reactions and behaviors within her own family following her brother's departure to college. Participant observation helps the researcher experience the environment from the perspective of those within it, thus gaining a more nuanced understanding of the dynamics at play.