As we only need to retain the principal components that account for most of the variance of the original features, we can either use the Kaiser method, a scree plot, or the percentage of variation explained as the selection criteria. The main purpose of a scree plot is to graph the component analysis results as a scree plot and find where the obvious change in slope (elbow) occurs. In this recipe, we will demonstrate how to determine the number of principal components using a scree plot.
Ensure you have completed the previous recipe by generating a principal component object and saving it in variable eco.pca
.