First, the data is visualized through bar chart as shown in Fig. 4. In order to showing the directly comparison, the young group and other age groups are separated as two bars in each day rather than combining in one bar. Surprisingly, in most day of a month, the number of riders who born before 1980 is more than who born after 1980. Only 7 days (7/5, 7/11, 7/12, 7/18, 7/19, 7/25, 7/26) young group ride more, which is out of expectation. It also indicates that the hypotheses may need to reverse and then test again.