Although Quizmaster's quiz is a good source, it's a bit misleading because some states like Massachusetts are number 1 due to it being difficult to spell for some people. I'm not saying to change anything in the quiz, I'm just letting others know for context on why some states are listed.
Thank you FlabberBapper. I decided to use an other quiz too after you wrote this, and noticed you were right. US States by First Two Letters in 30 Seconds, by Cosmokim, had different results, so I compared them and changed the results.
I guessed that Massachusetts and Connecticut would be there simply because many people do not know how to spell them correctly. Then I simply forgot Nebraska, duh.