In Texas, a Judge or Jury can give elect the Sentence (punishment). If you take an offer made pre-trial, whether it is from the Court or the District Attorney, then a Judge will sentence you per the agreement.
A plea bargain is generally the only way to know for sure what your sentence will be, however, in such an agreement you may be asked to admit the conduct that you have either been charged with, or a reduced offense.
Alternatively, the decision to go to trial offers a range in which the sentence may fall, to give an idea of the possible sentences. While trial can be seen as a gamble, since there are no guarantees, it may be the wisest decision based on your case facts and history.
Clients often ask, "What are my chances at trial, in percentages?" Unfortunately, there is no accurate way to predict a trial, let alone assign that prediction a percentage. Jurors are instructed to follow the law, but applying law to the facts of a case can be tricky.
All of us have predisposed notions of what is right or wrong, or how the law may fit into certain categories of conduct. In one case, a holdout juror may cause a mistrial, and yet, in another trial, a holdout juror may cave in to the pressures of the other jurors, ultimately giving in and delivering a verdict they are not comfortable with.
Trials are impossible to fully predict, but a good lawyer will set forth the pros and cons of going to trial, including the best and worst issues at hand.