Data was collected for 300 randomly selected 10 minute intervals. For each ten-minute interval, the number of people entering the atrium of a large mall were recorded. The data is summarized in the table below. Number Frequency of Guests 80 - 99 22 100 - 119 78 120 - 139 67 140 - 159 53 160 - 179 80 What is the class width for this GFDT? Class width =