You may want to research Siege... I've used it to load test this one when it was originally set up and other VPS's that I've configured - those that I configured on my own bare metal server and those that I hosted elsewhere.
There is a LOT involved in how these tests are done... you can have a site with very few users test poorly, and a site with numerous active users test great. Below are two examples
It's ALL in how you have your server configured (if running VPS or bare metal) and what resources are allocated, how many scripts you have running (usually for ads), how many web based fonts you link to (think Google fonts that aren't hosted on your domain)....
This site had almost 2800 active users online when I tested it...
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And this one gets this
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If you REALLY want to understand them, you have to do MORE than simply look at the numbers... you have to examine the waterfall and structure results and then on many things you can modify your setup to enhance those results.
Pay SPECIAL attention to that TBT... it has to do with scripts you run on your site.. frequently those are ad related.
Your TTFB is high, which IS related to your hosting environment and can indicated either an overloaded server or a poorly configured one.
And as a classic case of what I was referring to, your site is calling to Google Fonts, which is taking almost 3/4 of a second just to pull that font in (which is one of the things that testing grades you on). There is a way you can load those fonts locally from your website... but depending on other factors, it may still be faster to load them from Google.
Those tests are all OK, but they tend to make people obsess with the numbers. The main question you have to answer is how is the user interaction? If your site is crawling then it's time to get busy. If it's still responsive, don't worry about it.
