A New York Timesarticle published on April 24, 2007, reported the research of Dr. Giorgio Vallortigara, a neuroscientist at the University of Trieste, Italy, and his colleagues. In this study, the researchers investigated whether a dog's tail wags in a preferred direction in response to positive as opposed to negative stimuli. The researchers answered this question by recruiting 30 dogs that were family pets. Filming the dog's tail from above, they allowed each dog to view (through a slat in its cage) its owner, an unfamiliar human, a cat (positive stimuli), and an unfamiliar, dominant dog (a negative stimulus). Would it be appropriate for the researchers to use a parametric hypothesis test