Great start on an important topic. Quick extra info - For drawing a trend line it is often useful to have the intercept as well. Using y=mx+b line notation the

Great start on an important topic. Quick extra info - For drawing a trend line it is often useful to have the intercept as well. Using y=mx+b line notation the best fit intercept is: \hat{b} = \bar{y} - m * \bar{x} [1] Be great to see some pictures to illustrate the formulas and some mention of robust statistics as I find outliers to be a huge issue in application of statistical techniques. [1] http://en.wikipedia.org/wiki/Simple_linear_regression http://en.wikipedia.org/wiki/Simple_linear_regression