Added stuff
Merge pull request #1 from muschellij2/master

Added Some functions for Trying Chapter 2
first set of ch9 plots
Merge pull request #2 from hcorrada/master

first set of ch9 plots
adding chapter 13 RMD file
adding chapter 13 RMD file
adding updated chapter 13 RMD file in its own folder
adding updated chapter 13 RMD file in its own folder
Merge pull request #3 from swihart/master

First round of Chapter 13 from swihart: chapter 13.rmd in its own folder.