Week 4 - r, correlation, pearson and spearman

In the week 4 class we learned about correlating data and calculating a figure called "r". Excel sure is handy with these statistical calculations. I wonder what they did in "the old days". The Pearson and Spearman formulas can be used in different situations but usually do arrive at about the same number. One of the most difficult aspects of statistics and this class is remembering all of the formulas and concepts and which formula does what. It's a lot to take in in a short time. It's probably keeping my brain on its toes, so to speak.