Many studies have demonstrated that high blood pressure increases the risk of developing heart disease or having a stroke. It is also safe to say that the health risks associated with binge drinking far outweigh any benefits. A study published in Heath Magazine in 2010 suggested that a combination of the two could be a lethal mix. As part of the study that followed 6100 South Korean men aged 55 and over for two decades, men with high blood pressure who binge drank even occasionally had double the risk of dying from a stroke or heart attack when compared to teetotalers with normal blood pressure.
a. Is this an observational or experimental study?
b. Identify the explanatory and response variable(s).
c. Does the study prove that a combination of high blood pressure and binge drinking causes an increased risk of death by heart attack or stroke? Why or why not?