Romney and his supporters outspent Gingrich heavily on Florida television ads, many of which attacked the former speaker's character. None mentioned Gingrich's admitted past marital infidelities.
Overall, Romney's margin over Gingrich in Tuesday's voting held among women across every category of education and income.
Some of the data from Tuesday's exit poll suggested women's votes were influenced more by a personal distaste for Gingrich than by liking Romney. Men said they generally viewed Gingrich favorably by nearly 2-1, but women were about evenly divided. In contrast, women expressed slightly stronger positive feelings about Romney as a person than men did.
Among all voters Tuesday, just over half expressed favorable views of Gingrich personally, compared with about three-quarters who said the same about Romney.
Men divided about evenly between Gingrich and Romney over which man better understood average Americans' problems; women favored Romney. Asked if they would be satisfied with Gingrich as the GOP nominee, nearly six in 10 men said yes, while women were closely split.
About one in seven GOP primary voters was Hispanic, and that group preferred Romney by almost 2-1. About a third of Tuesday's voters were 65 or older - and they gave Romney almost a 5-3 edge, better than he did with younger age groups.
Gingrich prevailed among people who said they were very conservative. Romney had a big edge among those describing themselves as somewhat conservative, moderate, or liberal. The rivals split tea-party supporters about evenly, while Romney won strongly among all others.
About 6 in 10 Florida GOP voters said the economy was their biggest issue. They preferred Romney by about 20 percentage points.
Though Romney won among every income category, he did better with higher-income voters. Gingrich managed to tie him among voters who said they were falling behind economically. And Gingrich did better among the half of voters who said home foreclosures were a major problem in their communities than he did among those who said it wasn't so bad.
Those in the poll who voted early or by absentee ballot backed Romney by about a 2-1 majority
The survey of 2,835 Republican voters, conducted for AP and the television networks by Edison Research, included interviews Tuesday with 2,235 voters as they left polling places at 40 randomly selected sites in Florida, as well as phone interviews with 600 early or absentee voters. 23 to 29. The survey has a margin of sampling error of plus or minus 3 percentage points.