Try out the following exercises to revise the concepts learned so far:
- Look at the documentation on cor with help("cor"). You can see, in addition to "pearson" and "spearman", there is an option for "kendall". Learn about Kendall's tau. Why, and under what conditions, is it considered better than Spearman's rho?
- For each species of iris, find the correlation coefficient between the sepal length and width. Are there any differences? How did we just combine two different types of the broad categories of bivariate analyses to perform a complex multivariate analysis?
- Download a dataset from the web, or find another built-into-R dataset that suits your fancy (using library(help = "datasets")). Explore relationships between the variables ...