The average score is the sum of all of the estimates divided by their number. If you want to calculate the average score of high school diploma, it will take into account all the scores you put down in the diploma. In this case, will not include estimates for "intermediate" tests. For example, according to some long lasting disciplines students to take tests every semester, but the diploma is only the latest evaluation for differentiated test or exam throughout the course.
It should be remembered that normally in the diploma are put down and the scores for state exams, for coursework and for the thesis, and for the results of the practices of HEI. These assessments are also rolled up with everyone else.
The calculation of average score is the most convenient to make so: at first you think, how much you have in the diploma assessments "excellent", how many of the assessments "good" and how "satisfactory" grades. Summarize the points. Then summarize the number of evaluations. The first sum is divided by the second. In the end, and get your average score.
Example: student N. diploma is 18 rated as "excellent", 16 assessments "good" and 4 assessment satisfactory. The average score of the student N. is calculated as:

- 18 multiplied by 5. It turns out 90;

- 16 multiplied by 4. Turns 64;

- 4 multiplied by 3. It turns out 12;

- added 64 to 90 and 12. A total of 166 - all the scores of student N;

- added 18 to 16 and 4. Total 38 - all evaluation of student N;

- 166 divided by 38. It turns out something is 4.36. It is the student's GPA is N.