The mtcars dataset is a built-in dataset in R that contains data on the design and performance of various car models.
In this article explains how to load, explore, summarize and visualize the mtcars dataset in R.
Load the mtcars Dataset
To load the mtcars dataset we use data() function:
# Load dataset
data(mtcars)
Let see how we can get first six rows from mtcars dataset:
# Get first six rows
head(mtcars)
The below output shows first six rows from mtcars dataset.
Output:
mpg cyl disp hp drat wt qsec vs am gear carb
Mazda RX4 21.0 6 160 110 3.90 2.620 16.46 0 1 4 4
Mazda RX4 Wag 21.0 6 160 110 3.90 2.875 17.02 0 1 4 4
Datsun 710 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1
Hornet 4 Drive 21.4 6 258 110 3.08 3.215 19.44 1 0 3 1
Hornet Sportabout 18.7 8 360 175 3.15 3.440 17.02 0 0 3 2
Valiant 18.1 6 225 105 2.76 3.460 20.22 1 0 3 1
Summarize the mtcars dataset
We use summary() function to summarize mtcars dataset.
# Get statistical data
summary(mtcars)
The following output shows summary of mtcars dataset.
Output:
mpg cyl disp hp drat
Min. :10.40 Min. :4.000 Min. : 71.1 Min. : 52.0 Min. :2.760
1st Qu.:15.43 1st Qu.:4.000 1st Qu.:120.8 1st Qu.: 96.5 1st Qu.:3.080
Median :19.20 Median :6.000 Median :196.3 Median :123.0 Median :3.695
Mean :20.09 Mean :6.188 Mean :230.7 Mean :146.7 Mean :3.597
3rd Qu.:22.80 3rd Qu.:8.000 3rd Qu.:326.0 3rd Qu.:180.0 3rd Qu.:3.920
Max. :33.90 Max. :8.000 Max. :472.0 Max. :335.0 Max. :4.930
wt qsec vs am gear
Min. :1.513 Min. :14.50 Min. :0.0000 Min. :0.0000 Min. :3.000
1st Qu.:2.581 1st Qu.:16.89 1st Qu.:0.0000 1st Qu.:0.0000 1st Qu.:3.000
Median :3.325 Median :17.71 Median :0.0000 Median :0.0000 Median :4.000
Mean :3.217 Mean :17.85 Mean :0.4375 Mean :0.4062 Mean :3.688
3rd Qu.:3.610 3rd Qu.:18.90 3rd Qu.:1.0000 3rd Qu.:1.0000 3rd Qu.:4.000
Max. :5.424 Max. :22.90 Max. :1.0000 Max. :1.0000 Max. :5.000
carb
Min. :1.000
1st Qu.:2.000
Median :2.000
Mean :2.812
3rd Qu.:4.000
Max. :8.000
As we can see output the summary() function gives minimum, 1st quartile, median, mean, 3rd quartile and maximum values for each variable of dataset.
Get Dimension of mtcars Dataset
We use dim() function to get number of rows and column of dataset:
# Get rows and columns
dim(mtcars)
The following output shows total number of rows and column in dataset.
Output:
[1] 32 11
Get Column Names of the mtcars Dataset
Using names() function you can get column names of dataset:
# Get the columns names
names(mtcars)
As below output shows column names of mtcars dataset.
Output:
[1] "mpg" "cyl" "disp" "hp" "drat" "wt" "qsec" "vs" "am" "gear" "carb"
Visualize the mtcars Dataset
There are several types of charts you can use to visualize your data, and accordingly, there are different functions in R for each method.
To visualize the histogram you can use hist() function:
# Create histogram of values for hp
hist(mtcars$hp,
col='green',
main='Histogram',
xlab='hp',
ylab='Frequency')
The below snippet show histogram for hp variable of dataset.
Output:
If you want to plot boxplot then use boxplot() function:
# Create boxplot of values for hp
boxplot(mtcars$hp,
main='Distribution of hp values',
ylab='mpg',
col='black',
border='white')
The following output shows boxplot for hp variable of dataset.
Output:
To plot scatter plot you can use plot() function:
# Create scatter plot for mpg vs. wt
plot(mtcars$mpg, mtcars$wt,
col='steelblue',
main='Scatterplot',
xlab='mpg',
ylab='wt',
pch=19)
The below snippet shows scatterplot for mpg vs. wt column of dataset.
Output:
Using all this function you can explore mtcars dataset.
