Consider this original statement: "Most people are white." Its negation is: "It's not the case that most people are white." i.e. 0-50% people are white. Isn't this the equivalent of "Most people are not white"?

In contrast, given: "Most people are not white" Its negation is "It's not the case that most people are not white." i.e. 0-50% are not white. In this case, I know the negation is not equivalent to "Most people are white". It's not a binary cut here. Compared to the first statement, what changed? I'm not sure how to think about this.