Poll dates Oct. 30-Nov. 8, 2015. 542 Texas registered Republicans, error margin 4.21, 4.76 when adjusted for weighting (p. 2). Internet survey.
11/12/15, "UT/TT Poll: Cruz, Trump Tied; Clinton Well Ahead," Texas Tribune, Ross Ramsey
"U.S. Sen. Ted Cruz
and businessman Donald Trump are in a dead heat for the Republican
presidential nomination in Texas, according to the latest University of
Texas/Texas Tribune Poll.
With four months to go before the March 1 primary, each had the
support of 27 percent of likely Republican voters. Surgeon Ben Carson
and U.S. Sen. Marco Rubio of Florida were well back of the leaders at 13
percent and 9 percent, respectively....
The numbers have shifted some since the previous UT/TT survey in June — a poll conducted when a number of official and unofficial exploratory campaigns were still underway....
The two leading Republican candidates in the latest survey —
especially Trump — scooped up support that in June was going to two
candidates who have since left the race: former Texas Gov. Rick Perry and Wisconsin Gov. Scott Walker. Cruz had 20 percent in that June poll; Trump was back in the dust at 2 percent.
“The summer of Trump had not started when we did the last poll,” Henson said. “He was not really in the race.”...
The University of Texas/Texas Tribune internet survey of 1,200
registered voters was conducted from Oct. 30 to Nov. 8 and has an
overall margin of error of +/- 2.83 percentage points. Among registered
voters  in Republican primary races, the margin of error is +/- 4.21
percentage points; in Democratic primary races, it is +/- 4.57
percentage points. Numbers in charts might not add up to 100 percent
because of rounding."
"Disclosure: The University of Texas at Austin is a corporate sponsor of The Texas Tribune. A complete list of Tribune donors and sponsors can be viewed here."