This report uses the built-in R **`mtcars`** dataset to analyze the relationship between vehicle power and fuel mileage.
# Load the dataset
data(mtcars)
Below is a statistical breakdown of all components in the dataset, including standard metrics for weight, speed, and engine cylinders.
summary(mtcars)
## mpg cyl disp hp
## Min. :10.40 Min. :4.000 Min. : 71.1 Min. : 52.0
## 1st Qu.:15.43 1st Qu.:4.000 1st Qu.:120.8 1st Qu.: 96.5
## Median :19.20 Median :6.000 Median :196.3 Median :123.0
## Mean :20.09 Mean :6.188 Mean :230.7 Mean :146.7
## 3rd Qu.:22.80 3rd Qu.:8.000 3rd Qu.:326.0 3rd Qu.:180.0
## Max. :33.90 Max. :8.000 Max. :472.0 Max. :335.0
## drat wt qsec vs
## Min. :2.760 Min. :1.513 Min. :14.50 Min. :0.0000
## 1st Qu.:3.080 1st Qu.:2.581 1st Qu.:16.89 1st Qu.:0.0000
## Median :3.695 Median :3.325 Median :17.71 Median :0.0000
## Mean :3.597 Mean :3.217 Mean :17.85 Mean :0.4375
## 3rd Qu.:3.920 3rd Qu.:3.610 3rd Qu.:18.90 3rd Qu.:1.0000
## Max. :4.930 Max. :5.424 Max. :22.90 Max. :1.0000
## am gear carb
## Min. :0.0000 Min. :3.000 Min. :1.000
## 1st Qu.:0.0000 1st Qu.:3.000 1st Qu.:2.000
## Median :0.0000 Median :4.000 Median :2.000
## Mean :0.4062 Mean :3.688 Mean :2.812
## 3rd Qu.:1.0000 3rd Qu.:4.000 3rd Qu.:4.000
## Max. :1.0000 Max. :5.000 Max. :8.000
We expect cars with higher horsepower to consume more fuel, resulting in lower miles per gallon (mpg). The scatter plot below visualizes this negative correlation:
# Create a clear scatter plot
plot(x = mtcars$hp,
y = mtcars$mpg,
xlab = "Gross Horsepower (hp)",
ylab = "Miles Per Gallon (mpg)",
main = "Vehicle Horsepower vs. Fuel Efficiency",
pch = 19, # Use solid circles for plotting points
col = "darkblue", # Point color
las = 1) # Rotate axis labels horizontally
# Add a trend line to illustrate the path
abline(lm(mpg ~ hp, data = mtcars), col = "red", lwd = 2)
As clearly shown by the downward-sloping trend line in the plot, there is a distinct negative correlation between horsepower and miles per gallon. Cars built with more powerful engines generally sacrifice fuel efficiency.