A full-page magazine ad for a new medication describes a clinical trial as follows: "Four different groups of subjects were given the same dosage. The groups are listed in the table below. In both 40 to 60 age groups, the medication reduced symptoms in 80% of patients. In both 20 to 40 age groups, the medication reduced symptoms in 40% of patients." Which of the following correctly describes this study?

Question

A full-page magazine ad for a new medication describes a clinical trial as follows: "Four different groups of subjects were given the same dosage. The groups are listed in the table below.  In both 40 to 60 age groups, the medication reduced symptoms in 80% of patients. In both 20 to 40 age groups, the medication reduced symptoms in 40% of patients." Which of the following correctly describes this study?