If you've ever come across a table listing all the ACT score percentiles, you may have seen the ACT standard deviation listed at the bottom for composite and section scores. Sadly, there is no explanation for what the standard deviation being that value means; instead, the tables just throw the data out there and move on.
So how does knowing the mean and standard deviation of ACT help you? We'll discuss what standard deviation is and what it means for you and your ACT score in this article.