A university runs a new class designed to improve the Freshman experience. The hypothesis is that participation in the new class will improve attitudes toward school. To evaluate the hypothesis, the research team uses a test statistic to compare the sample mean from a sample to the mean of a national norm group. The assumed population mean (the expected mean if the null is true) is 20, the mean from a sample of 25 students is 22, and the standard error is 4. What is the value of the test statistic from this analysis