An investigator compares an average standardized depression score in two groups of hypertensive patients: those who take beta-blockers and those who do not.  Which of the following tests is most likely to be employed by the investigator to analyze the study results?

A study is conducted to assess the association between hormone replacement therapy (HRT) in post-menopausal women and the level of serum C-reactive protein (CRP).  The data from the study are presented below:

Which of the following is the best statistical method to assess the association between HRT and elevated CRP levels?

It is claimed that a new drug induces rapid and sustained weight loss by affecting triglyceride metabolism in the small intestine.  The body mass index of 100 patients is calculated at baseline and compared to the value after 1 year of treatment with the drug.  Which of the following tests is most likely to be employed by the investigators to analyze the study results?

A clinical study evaluates the role of thymectomy in patients with myasthenia gravis who do not have an anterior mediastinal mass on chest CT scan.  Out of 9 patients who undergo thymectomy, 7 show sustained improvement after one year of follow-up.  Out of 20 patients treated conservatively, 8 show sustained improvement after one year of follow-up.  Which of the following tests is most likely to be employed by the investigators to analyze the study results?