Yes. Most people who point to low standardized test scores in Southern states, and snicker about sterotypes, are probably unaware that the region is unusually insistent on high school students taking either the SAT or ACT.

Many Southern states require one or the other as a requirement for high school graduation, period, whether you're planning for college or not. And many others that do not require it pressure all students to take it by default:

https://magoosh.com/hs/act/2017/states-that-require-the-act-...

So of course your statewide averages will be lower than the national average, when the testing population in other regions is limited to college-prep students only.