Researchers wanted to assess the effect of low alcohol consumption on reaction time in seniors. Their belief was that even low levels of alcohol consumption can impair the ability to walk, thereby increasing the likelihood of falling. They identified 13 healthy seniors who were not heavy consumers of alcohol. The experiment took place in late afternoon. Each subject was instructed to have a light lunch (such as a sandwich) and not to drink any caffeinated drinks in the 4 hours prior to arriving at the lab. The seniors were asked to walk on a treadmill on which an obstacle would appear randomly. The reaction time was measured by determining the time it took the senior to lift his or her foot upon the appearance of the obstacle. First, each senior walked the treadmill by consuming a drink consisting of water mixed with orange juice with the scent and taste of vodka. The senior was then asked to walk on the treadmill. The senior was then asked to drink two additional drinks (40% vodka mixed with orange juice). The goal was to have the senior reach a blood alcohol concentration around 0.05%. The senior then walked on the treadmill again.
The average response time increased by 19 milliseconds after the alcohol treatment. The researchers concluded that response times are signiﬁcantly delayed even for low levels of alcohol consumption.
(a) What type of experimental design is this?
(b) What is the response variable in this experiment? Is it quantitative or qualitative?
(c) What is the treatment?
(d) What factors were controlled and set at a fixed level in this experiment?
(e) Can you think of any factors that may affect reaction to alcohol that were not controlled?
(f ) Why do you think the researchers used a drink that had the scent and taste of vodka to serve as the treatment for a baseline measure?
(g) What was the conclusion of the study? To whom does this conclusion apply?