During summer season, it is expected that more tourists will visit New York City during weekends and make use of Citibike to explore. The Citibike Mini-project selected the rider's data of 2017 August to measure if the proportion of short-term riders (tourists) is higher during the weekends. Mann-Chi-Square test is performed based on two randomly extracted samples (one sample from weekday rides, and the other one from weekend rides; the sample size is 5000). The result rejected the null hypothesis. which demonstrates that the proportion of short-term riders riding during weekend is higher than the proportion of short-term riders riding during weekdays.