![What are biplots?](https://blogs.sas.com/content/iml/files/2019/11/biplotCOV-480x336.png)
Principal component analysis (PCA) is an important tool for understanding relationships in continuous multivariate data. When the first two principal components (PCs) explain a significant portion of the variance in the data, you can visualize the data by projecting the observations onto the span of the first two PCs. In