Shock poll: Donald Trump leads Jeb Bush 26-20 percent … in FloridaThere are reasons for skepticism. Last year, Daily Kos's David Nir criticized the track record and methodology of St. Pete Polls :
For the first time this year, Donald Trump tops a state poll of GOP presidential candidates in Florida.
A St. Pete Polls survey released on Wednesday shows the New York businessman with 26 percent support, with Jeb Bush in second place with 20 percent.
Wisconsin Gov. Scott Walker is in third place with 12 percent, and Marco Rubio is in fourth place with 10 percent. He’s followed by Dr. Ben Carson at 5 percent, Ted Cruz and John Kasich at 4 percent, and Rand Paul at 3 percent....

Nir specifically criticized St. Pete for having a pro-Republican lean and for conducting one-day robocall surveys. But a pro-GOP bias wouldn't matter in this case because it's just a poll of Republicans, and the pollster tells us this survey was conducted over the course of eleven days, not one.
But that's the only criticism of the pollster. When this story broke yesterday, Dave Weigel tweeted a link, and some of his readers picked apart the numbers:
@daveweigel Forget the topline, look at those demographics
62% male
92% white
80% age 50+
— Micheál Keane (@aexia) July 29, 2015
@daveweigel Incredible demos--33% age 70+, 80% age 50+. I assume the poll was taken before the early bird special.
— Steve($10B)Zorowitz (@szorowitz) July 29, 2015
Does it make sense in Florida that the 92% of the Republicans surveyed were white, or that (to be specific) 79.9% were 50 or over, and 32.5% were 70 and over?
Well, maybe it does make sense. The respected Edison Research exit-polled the 2012 Florida Republican primary, and 78% of its respondents were 45 or older, while 36% were 65 and older. Also, 83% were white (1% each were black, Asian, and "other," while 14% were Hispanic, of whom 8% were Cuban). So the St. Pete numbers aren't that far off.
The St. Pete gender skew is weird, however -- 61.9% male? Really? (Edison's 2012 exit-poll respondent poll was 51% male.) However, in the St. Pete poll, Trump wins among women as well as men, though men like Trump more (men: 28.2% Trump, 20.3% Bush; women: 23.2% Trump, 19.6% Bush).
So, yes, Trump may really be leading in Florida.