Cases tend to be data intensive. There is usually too much data available to reasonably analyze everything. Kevin explains how hypotheses help in such situations.
Kevin’s body language and response to Michael’s requests for more data provides strong hints to the nature of the case. Moreover, Michael’s approach is too simple.
Partners will guide candidates to the central issues. Kevin does the same by encouraging Michael to think about how the size differences between the markets.
This scene demonstrates the manner in which interviewers communicate. While they may not use words like brainstorm, the candidate must recognize the request.