A Scatter plot matrix is a useful device to display a miniature Scatter plot of every variable in your dataset against every other variable. The resulting display gives you a quick scan to determine variables that may be related.
Use this script:
# load the iris dataset
data <- read.csv("http://archive.ics.uci.edu/ml/machine-learning-databases/iris/iris.data")
#Let us also clean up the data so as to be more readable
colnames(data) <- c("sepal_length", "sepal_width", "petal_length", "petal_width", "species")
pairs(data)This produces this graphic:
The pairs graphic shows petal width and petal length as related (fairly good straight lines of the plot points), and little relationship between sepal length and sepal width.