Based on a large national sample of working adults, the U. S. Census bureau reports the following information on travel time to work for those who do not work at home: lower quartile is is 7 minutes, the median is 22.4 minutes and upper quartile is 31 minutes. Also given was the mean travel time, which was reported as 18 minutes.
a. Is the travel time distribution more likely to be approximately symmetric, positively skewed, or negatively skewed? Explain your reasoning based on the given summary quantities.
b. Suppose that the minimum travel time was 1 min and that the maximum travel time in the sample was 205 min.
c. Were there any mild or extreme outliers in the data set? How can you tell?