What is the research question for this table? What's the kind of study conducted? What is the study size?

Table 2. Change in cholesterol (before-to-after-treatment, baseline to first follow-up visit) by drug treatment. *Assume each trial has different participants Difference from before and after treatment Mean Type of Number of (change in Standard Trial Treatment Participants (n) cholesterol) Deviation Trial A Placebo 1000 132.5 14.7 Drug A 1000 120.7 12.3 Trial B Placebo 1500 136.6 15.2 Drug B 1500 127.2 13.3