Chapter 7: Carbon monoxide emissions (in grams per mile) of 794
cars.

Col 1: Interval
Col 2: Midpoint
Col 3: Frequency

       0 -  24      12        13
      24 -  48      36        98
      48 -  72      60       161
      72 -  96      84       189
      96 - 120     108       148
     120 - 144     132        85
     144 - 168     156        45
     168 - 192     180        30
     192 - 216     204        10
     216 - 240     228         5
     240 - 264     252         5
     264 - 288     276         1 
     288 - 312     300         2
     312 - 336     324         1
     336 - 360     348         1