sixty subjects were randomly divided into two groups to study the effects of alcohol on reaction time. the members of one group consumed a specified amount of alcohol, and members of the other group had a nonalcoholic beverage. the reaction time of both groups were measured before and after the beverage. a) what is the response variable? b) what is the treatment? c) what is an experimental unit? d) what is the purpose of one group drinking a nonalcoholic beverage? e) are any extraneous variables possible confounded with the treatment? if yes, identify and explain. f) is this study an observational study or an experiment? explain