Suppose a financial adviser would like to make the claim that his clients pay annual credit card interest that is more than 16 hundred dollars, on average. Several of his customers do not believe him, so the financial adviser decides to do a hypothesis test, at a 10% significance level, to persuade them. He conducts a financial analysis on 21 of his customers and calculates the sample average to be 17.8 hundred dollars. Working through the testing procedure: