A report from Texas Transportation Institute (Texas A&M University System, 2005) on congestion reduction strategies looked into the extra travel time

(due to traf fic congestion) for commute travel per traveler per year in hours for different urban areas. Below are the data for urban areas that had a population of over 3 million for the year 2002.

Urban Area Extra Hours per Traveler per Year Los Angeles 98 San Francisco 75 Washington DC 66 Atlanta 64 Urban Area Extra Hours per Traveler per Year Houston 65 Dallas, Fort Worth 61 Chicago 55 Detroit 54 Miami 48 Boston 53 New York 50 Phoenix 49 Philadelphia 40

a. Compute the mean and median values for extra travel hours. Based on the values of the mean and median, is the distribution of extra travel hours likely to be approximately symmetric, positively skewed, or negatively skewed?

b. Construct a modi fied boxplot for these data and comment on any interesting features of the plot.