For your first question. The two columns you are looking at, Entered and Answer Preview give what the student entered and a type set version of the answer which is most useful for formulas, etc.
For this problem, the third answer is indeed incorrect. The correct answer is .2513 not 2153. As a prof you can view the correct answers anytime. Students can see them only after the answer date.
For your second question, in problems you will see things like
$a= random(5,10,1);
i.e. let $a be a random number from 5 to 10 with stepsize 1.
If you replace this by, e.g.
#$a= random(5,10,1);
$a= 7;
there will be no radomization for $a. You will have to do this for all random variables. Note that # means every that follows on that line is a comment.
Good luck with WeBWorK.
Arnie