A recent study examined "sidewalk rage" in an attempt to find insight into anger's origins and offer suggestions for anger-management treatments (The Wall Street Journal, February 15, 2011). "Sidewalk ragers" tend to believe that pedestrians should behave in a certain way. For instance, slower pedestrians should keep to the right or should step aside to take a picture. If pedestrians violate these "norms," then ragers feel that the "violaters" are breaking the rules of civility. Since anger is associated with a host of negative health consequences, psychologists suggest developing strategies to quell the rage. One possible strategy is to avoid slow walkers. A portion of the study looked at the average speed of walkers (feet per second) in Lower Manhattan and found that average speeds differ when the pedestrian is distracted by other activities (smoking, talking on a cell phone, tourism, etc.) or exhibits other traits (elderly, obese, etc.). Sample data were obtained from 50 pedestrians in Lower Manhattan. Each pedestrian's speed was calculated (feet per second). In addition, it was noted if the pedestrian was smoking (equaled 1 if smoking, 0 otherwise), was a tourist (equaled 1 if tourist, 0 otherwise), was elderly (equaled 1 if over 65 years old, 0 otherwise), and/or was obese (equaled 1 if obese, 0 otherwise). Each pedestrian is associated with no more than one of these four characteristics/traits. The accompanying table shows a portion of the data.

Data for Case Study 17.1 Pedestrian Speeds with Defining Characteristics/Traits

In a report, use the sample information to:
1. Estimate Speed = β0 + β1Smoking + β2Tourist + β3Elderly + β4Obese +

2. Interpret the slope coefficient of tourist. Interpret the intercept. Predict the speed of an elderly pedestrian. Predict the speed of an obese pedestrian.

3. Are the explanatory variables jointly significant in explaining speed at the 5% significance level? Are all explanatory variables individually significant at the 5% level? What type of pedestrian should a “sidewalk rager” avoid?

Smoking Speed 3.76 3.82 Tourist Elderly Obese 1 5.02 0 0 0 0