1. Introduction
CitiBike is a privately owned public bicycle sharing system serving New York City and Jersey City, New Jersey.\cite{wikipedia} It is the nation's largest bike share program, with 10,000 bikes and 600 stations. There are two user types, 'Customer'(mainly visitors and tourists) and 'Subscriber' (mainly New York locals).\cite{nyc}The question we want to answer in this article is that whether the 'Customer' are more likely than 'Subscriber' to use CitiBike during working hours (9:00 - 17:00). To know that can be helpful for CitiBike owner company (NYC Bike Share, LLC) to make their sales and operation strategies. For example, If we want to provide some targeted services or advertisement to the 'Customer'(mainly visitors and tourists), this analysis can give the best time span of providing.