That diagram provides you about 260 last minutes of Server CPU usage and measured in percents.
As you can see my SQL Server is mostly doing nothing and only during that blog-post writing in the last half and hour or so it is heavily running test scripts to over-utilize my CPU, but it still barely goes more than 60% of CPU (Blue line).
The Red line represents all other processes besides of SQL Server and you can tell if anything else from outside is impacting your performance.
Combined with Glenn Berry’s diagnostic queries, you could generate some quick analytics. I’d still use R for anything more than slightly complicated, but this is great for those environments in which you don’t have good alternative tooling.