Answer:
I believe that the best answer to the question: Is there enough evidence to conclude that alcohol and depression are related? Would be: there is enough evidence to show a level of correlation between the two variables, but not enough to show that one leads necessarily to the other, or what is known as a causal relation.
Step-by-step explanation:
The intent for this survey performed by Gallup was to establish the relationship that existed between alcohol consumption and depression, especially clinical depression, given that previous data shows that there is a relationship between the two. However, the survey failed in establishing the causal relationship between the two because of the questions it used. In the first case, the questions only led to know if the people in the sample could be classified as non-drinkers, moderate drinkers and heavy drinkers. These questions established then the presence, or absence of alcoholic consumption. The second set of questions tested to see if people had ever, in their lives, been diagnosed with clinical depression, which yielded just two options: yes, and no. The answers that would come from the questions, and the results extracted from the two sets of questions manage to show that either the two variables: alcoholism and depression, appear together, or not at all, or there may be the appearance of one, without that of the other. Therefore, in the end, what the survey manages is to establish a statistical probability of correlation, but not necessarily responds the question of the researchers: that there is in fact, a causal relationship between the two variables, as the survey does not prove that depression necessarily leads to alcohol consumption.