First.Of the 35 questionnaires,five questionnaires were invalid.The reason for this is that this five questionnaire respondents did not see the steering problem,all part of the questionnaire answered.
Second,this questionnaire is only a multiple choice,but because thequestionnaire answers did not indicate what is radio which is selected,which is caused by many respondents misunderstanding,the single problem with multiple choice form answer,this gives us the data inputcaused great distress.
Third,there are two open questions in the questionnaire,open-ended question because the answer is too broad,it is difficult to statistics.