Dr. Bowman has developed a coding system for aggressive behaviors displayed in comic books. She has her assistants read comic books published between 1980 and 1984 and record the number of aggressive acts displayed in each comic. She also has her assistants read comic books published between 1985 and 1989 and record the number of aggressive acts displayed. This approach to studying aggressive behavior may best be categorized as .

A62-year-old man is being treated for an acute myocardial infarction. he originally came to the ed with substernal chest pain and diaphoresis. given his risk factors of hypertension, diabetes, tobacco use, and family history, he is considered high risk. an ecg in the ed reveals a left-bundle branch pattern, and cardiac enzymes are elevated slightly. after a focused evaluation in the ed, the patient receives iv thrombolytics. although his bundle branch pattern never resolves, the patient is chest pain-free and haemodynamically stable after thrombolysis. two days later, however, the patient reports episodes of recurrent chest discomfort and shortness of breath overnight. in evaluating for potential myocardial reinfarction, which of the following is the most appropriate diagnostic test? - creatinine kinase- dynamic ecg changes- lactate dehydrogenase- myoglobin levels- troponin i level