This site focuses on using the LRT to compare two competing models.
This chapter of the "Concepts and Applications of Inferential Statistics" online textbook describes in detail the Kruskal-Wallis test, it's formulas, variables, and procedures using an example involving wine-tasters.
This page gives a description of correlation, Pearson's r, Spearman's rho. There are some scatterplots illustrating the different values of r.