THE RESULT
What the data shows
The largest computed metric is 32.4 for (0.0, 2000.0]; the smallest is 14 for (4000.0, inf]. Metric: median_mpg (Miles per US gallon).
Engine size, model year and origin differ across weight bands.
| weight band | vehicles | median mpg | p25 | p75 |
|---|---|---|---|---|
| (0.0, 2000.0] | 44 | 32.4 | 29.95 | 36.02 |
| (2000.0, 2500.0] | 103 | 29 | 25 | 33.9 |
| (2500.0, 3000.0] | 83 | 24 | 21.3 | 27 |
| (3000.0, 3500.0] | 59 | 19.1 | 17.65 | 20.9 |
| (3500.0, 4000.0] | 45 | 17 | 15 | 18.5 |
| (4000.0, inf] | 64 | 14 | 13 | 15.12 |
THE METHOD
From source to answer
Robust fuel-economy summaries by weight band.
The Python source exposes this study’s transformations. The complete project download includes shared preparation and evaluation routines.
THE NEXT DECISION
What follows from the finding
Use controlled vehicle comparisons before attributing fuel economy differences to weight alone.
Where the conclusion stops
Historical city-cycle vehicle observations are not current fleet performance. Vehicle mix and model year are confounded. A '?' horsepower value means missing, not zero.
Related studies may reuse observations or holdouts. These are historical analyses; associations and backtests do not demonstrate commercial impact. Further model tuning needs new, untouched evaluation data.