=+3.26 ● U.S. Census data for San Luis Obispo County, California, were used to construct the following frequency distribution for commute time (in minutes) of working adults (the given frequencies were read from a graph that appeared in the San Luis Obispo Tribune [September 1, 2002] and so are only approximate):

Commute Time Frequency 0 to ,5 5,200 5 to ,10 18,200 10 to ,15 19,600 15 to ,20 15,400 20 to ,25 13,800 25 to ,30 5,700 30 to ,35 10,200 35 to ,40 2,000 40 to ,45 2,000 45 to ,60 4,000 60 to ,90 2,100 90 to ,120 2,200