49-43 Rubio/Clinton
47-43 Bush/Clinton
Favorables (favorable, unfavorable, neutral, don't know):
46-27-25-2 Rubio
45-31-23-1 Bush
41-39-19-1 Clinton
HOW THE POLL WAS CONDUCTED
This poll was conducted by Mason-Dixon Polling & Research, Inc. of Jacksonville, Florida from April 14 through April 16, 2015. A total of 625 registered Florida voters were interviewed statewide by telephone.
Those interviewed on land-lines were selected by the random variation of the last four digits of telephone numbers. A cross-section of exchanges was utilized in order to ensure an accurate reflection of the state. Those interviewed on cell phones were selected from a list of working cell phone numbers.
Quotas were assigned to reflect voter turnout by county. The margin for error, according to standards customarily used by statisticians, is no more than ±4 percentage points. This means that there is a 95 percent probability that the "true" figure would fall within that range if all voters were surveyed. The margin for error is higher for any subgroup, such as a gender or age grouping.
This section also contains an over-sampling to include 400 registered Democratic voters. These additional voters were only asked the questions related to the Democratic primary election. They were not included in the general election section. The margin for error on this Democratic voters sample is no more that ±5%.
http://mason-dixon.com/wp-content/uploads/2015/04/FL-POLL-APRIL-20TH-RELEASE-PRESIDENTIAL-CLINTON-BUSH-RUBIO.pdf