How is vocal range determined?

Question:

How is vocal range determined?

For instance, would a woman be classified a soprano for how high she can go? Or, an alto for how low she can go?

Additional Details

5 months ago
Thanks for all the answers! I'd been wondering about that for quite awhile. And since all the answers are so good, I'm not gonna pick one.

Thanks again!

Best Answer - Chosen by Asker: 5 months ago
Thanks for all the answers! I'd been wondering about that for quite awhile. And since all the answers are so good, I'm not gonna pick one.

Thanks again!