I used http://www.usingenglish.com/resources/wordcheck/list-common+words.html as my source, so I can't say one way or the other whether a certain word should have been on here or not. If the source you linked, however, is more reliable/accurate, then I could definitely alter the quiz to fit its data. :)
^ True. I guess I wanted to find my own source, rather than basing it off of someone else's quiz. Although, yes, I could look at that source, then go from there. I like that quiz; I just thought I would make it a little more specific (and harder) by doing one letter at a time. I myself didn't do great on this quiz! Some of the words just didn't come to mind. This is only like, my second quiz I've made, so I'm definitely open to suggestions and feedback! So thank you all. :)