Observational and Inferential analysis of vehicles in 1974 (mtcars)
| R | version |
|---|---|
| dplyr | version |
| ggplot2 | version |
| factoextra | version |
| FactoMineR | version |
| plotly | version |
| broom | version |
- Is an automatic or manual transmission better for mpg?
- Quantify the mpg difference between automatic and manual transmissions.
| Feature | Description |
|---|---|
| mpg | Miles / US Gallon |
| disp | Displacement - Measures the overall volume in the engine as a factor of cylinder circumfrance, depth and total number of cylinders. ‘Proxy for the total amount of power the engine can generate.’ |
| hp | Horsepower |
| drat | Rear Axle Ratio - The number of turns of the drive shaft for every one rotation of the wheel axle |
| wt | Weight (lb/1000) |
| qsec | 1/4 time - A performance measure, primarily of acceleration |
| vs | Engine Cylinder Configuration - (VShape = 0 : StraightLine = 1) |
| am | Transmission Type - (Auto = 0 : Manual = 1) |
| gear | Number of Forward Gears - Auto = (3 : 4), Manual = (4 : 5) |
| carb | Number of Carburetors - Engines with higher displacement typically have higher barrel configuration |
To Quantify the difference I choose to use a Regresion Model because.
-
I was able to get good most of the variance explanined
-
The error was low
-
Highly Interpretable, which leads to producing Coeffiecents for Inferential Statistics
| Intercept | am (Manual) | am (Automatic) | am:wt | Rsquared | RMSE |
|---|---|---|---|---|---|
| 29.314 | 13.352 | -3.282 | -8.051 | 83% | 3.45 |
-
If your vehicle weighs below 2,500lb (2.5 * 1000). I would say go for the manual transmission because it has a better mpg.
-
If the weight of a vehicle is above 2.500lbs there not much of a difference between manual and automatic
-
According to the model Automatic Transmission vehicles have an avg mpg of 29.31. As weight increases by 1 unit (1000/lbs), for an Automatic vehicle the mpg will drop by -3.28
-
If the vehicle has a Manual Transmission the mpg increases by 13.35. As weight increases by 1 unit (1000/lbs), for a Manual vehicle the mpg will drop by -8.05