Recently, Experian reported that the average credit score for a new-car loan was 753. Suppose Ally Financial, a bank holding company that finances car loans, would like to test the hypothesis that the average credit score has increased since the Experian report. A random sample of 20 new-car loans had an average credit score of 764.2 with a sample standard deviation of 34.5. Ally Financial would like to set = 0.05. The test statistic for this hypothesis test would be ________.