## Elementary Statistics: A Step-by-Step Approach with Formula Card 9th Edition

The histogram below shows the comparison of the two distributions. The number of cities remain unchanged for the 15-19 and 40-49 $g/m^3$ ranges. In the 25-39 $g/m^3$ range, the number of cities now is less than that of 5 years ago. And the number of cities now for the 10-14 $g/m^3$ region is more than that of 5 years ago.