The weight of a question within a quiz is the ratio of its worth compared to other questions in a quiz. If one question has a weight of 2 and all questions have a weight of 1 then that 2 point question is worth twice as much as its peers.
The numbers in the far-right column on the Edit Quiz page represent individual value (worth) for each question.
This is, by default, one (1) point but it can be set as a different value when cratering quizzes. As an instructor you can alter the weight of individual questions from their default for a single quiz. For example, you might want an essay question to be worth five (5) points and a true/false question to be worth one (1) point on a final exam.
Enter the Quiz you wish to modify
From the Secondary navigation at the top of the page click the Questions item.
Locate the question to wish to change the weight of.
Click on the Edit Maximum Mark icon 
to the far right of the question.
Edit the value in the box that appears.
Hit the Enter/Return key to save your changes.
Repeat as desired for each question in this quiz.