Which of Mill's Methods Is Illustrated in the Following Passage

Which of Mill's Methods is illustrated in the following passage? If, in your opinion, the conclusion reached indicates that an inadequate hypothesis was employed, explain why and formulate a better hypothesis.
Benjamin observed the hibernation pattern of the small brown bear over a period of fifteen years. In the first five years the winters were unseasonably warm, with temperatures rarely dipping below freezing, and during that period of time Benjamin noticed that the bears hibernated very little. During the next five years, the winters were quite harsh (temperatures consistently below 0°) and the bears were in hibernation throughout most of the winter. Over the past five years the winters have been about average with temperatures consistently hovering in the 20s, and Benjamin has noticed that although the bears were more active than they had been the previous five years, they were not nearly as active as they had been during the first five years of the study. He concluded on the basis of these observations that there is a direct causal relationship between the winter temperatures and the length of hibernation for the small brown bear.