Exercise 5

In this activity, we looked at a dataset consisting of four measurements of 150 irises. These measurements are sepal length, sepal width, petal length, and petal width.

1. Find the first principal component $\uvec_1$ and describe the meaning of its four components. Which component is most significant? What can you say about the relative importance of the four measurements?

2. When the dataset is plotted in the plane defined by $\uvec_1$ and $\uvec_2$, the specimens from the species iris-setosa lie on the left side of the plot. What does this tell us about how iris-setosa differs from the other two species in the four measurements?

3. In general, which species is closest to the “average iris”?