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

Short Answer

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.
Nettie's car flunked the VET test in Louisville with carbon emissions of 25, 000 parts per million. After replacing the muffler and tailpipe, Nettie had her car retested and it passed-this time with carbon emissions of only 2,500 parts per million, well within the range of emissions for the normal operation of a car. On the basis of this experience, Nettie decided to have her muffler and tailpipe checked before each VET test in the future.