A restaurant implements a new Point of Sale system that offers customers the option to add a tip. The management wants to test whether this new system leads to an increase in tipping from customers. The average tipping rate before the implementation of the new system was 15%. After implementing the new system, they collect data from the first 200 transactions, and find that the tipping rate among these new transactions is 0.195, with sample standard deviation 0.396. Formulate an appropriate null hypothesis and alternative hypothesis and compute the value of the test statistic.