This tutorial demonstrates how to calculate multiple Correlations in R as well as demonstating how to create a scatter plot matrix. The video also introduces the quantmod financial modeling library for R, used to download data from various sources. Quantmod has extensive functionality in the financial modeling space. Visit their site for documentation.
The correlation coefficient is a statistic that gives an indication of how strongly two variables are related. The result of calculating correlation is a number between -1 and 1. Numbers closer to either extreme indicate a stronger relationship, while a number closer to 0 indicates a weak or even no relationship. This statistic is also known as Pearson's product moment correlation coefficent or simply "r".
You can download the file used in the video by visiting here