Resting pulse rate is an important measure of the fitness of a person's cardiovascular system, with a lower rate indicating greater fitness. The mean pulse rate for all adult males is approximately 72 beats per minute. A random sample of 50 male students currently enrolled in the Business School at a major university was selected and the mean resting pulse rate was found to be 76 beats per minute with a standard deviation of 12 beats per minute. The experimenter wishes to test if the students are less fit, on average, than the general population. Test the researcher's claim at the 0.05 significance

What is the test statistic?