Can anyone explain about the "Cutoff z-score". Is there a standerd definition for the cutoff z-score?
In Sri lanka there is the university entrance exam is called the "Advanced level" examination. In this examination students are given a z-score, which I understand correctly. Suppose I have done physics, chemistry and mathamatics at this exam. Then my z-score would be the average z-scores of the above three subjects.(given to four decimals)
After this the students are to apply for the university courses. We could apply for a several courses according to our order of preference. The selection procedure is done as follows; Suppose they select 1000 students for engineering. Then the first 50% is selected among the people who have applied for engineering and got the highest z-score. The next 50% will be selected districtwise(Srilanka have 25 districts).
That is, ; therefore the first 500 students are selected according to their z-score.
Suppose the district I am living (which I take as A) has a population percentage of 7% ;
Then ; therfore a 35 people are selected from district A
Similarly there is a certain number of places given for each district.
After this they publish a "cutoff z-score" which tells us whether we are selected to a particular course of study or not. Suppose the cutoff z-score of engineering is 1.8902 and my z-score is less than this. Then I am not selected to engineering.
The calculation of the cutoff z-score is not published anywhere. But the handbook of the university selection says that, "It is important to note that the Cut-of-point may vary from year to year dependig on factors such as performance of stdents, number of places available in the university etc."
This is the summary of the things that I do know. I want to know how the cutoff z-score is calculated. I know you may not be able to give a presice discription for the calculation procedure. But any idea would be of great importance. Please bear with me if the discription I have given it is not clear and I would be always willing to clarify.