Do pets help relieve stress? Forty-five self-reported dog lovers were recruited for a study [ABTK91]. The data are summarized in [BM09]. Fifteen subjects were assigned to each of three treatment groups. The subjects' heart rates were monitored while they performed a stressful task either alone (group C), with a good friend in the room (group F), or with their dog in the room (group P). Mean heart rates and treatment are available in the pet stress data set.
a) Use diagnostics to decide if an ANOVA analysis is appropriate for this data.
b) If it is appropriate, perform the model utility test and interpret the results.