1. This is a fragment because the author does not say anything more about the people who moved from New York to Florida.
2. This is a fragment because the author does not complete saying what was double to the number for the past decade
3. This is a fragment because the author doesn't finish his/her sentence about the people who moved to New York, New Jersey, and Ohio.
4. This is a fragment because the author does not tell us what or who tends to be poorer, older, and alone.