Guyz it is all comparative marking....
It depends not only how you do...but how all the others are doing around you...
Even the marking scheme is made by comparison...
So this means that it depends on the stupidity (or rarely intelligence) of the candidates, and on the difficulty of the paper...
This is the reason why some years the marks for A are so high and in other years they are really low.
So if the paper was really hard and every1 was getting a really low grade then the Grade threshold for the year would be low....and vice versa...
for example in 2007, you just needed 64.5% to get an A....
That is a really low mark if compared, but in that year the papers were really tough... I personally know it cuz my brother left the last page in maths paper 4...BUT HE STILL GOT A*....Cuz paper was hard... and he did most of hard questions... and he got the marks over there....and therefore even when his marks were low he got A*....
They calculate (at least for physics in the following way) ---> 100*((.3*(Mark In paper 1/40))+(.5(Mark in Paper 3/80)+(.2(Mark in paper 6(or 5)/40))
Then they decide a grade threshold...
they DO NOT release info about A* to the public....
There are many rumours about how it is calculated...
Some people say --> difference between A & B equals difference between A and A*
Others say --> mark for A grade plus maximum mark divided by 2 (average of max mark and A threshold...
Some people say that it is plotted and the a percentile is taken....
Some say that if you get A in all papers you get an A* on the report card
There are many stories like this...but we will never know how to calculate grade for A*, Though we can calculate our final grade....
As I showed above.
By the way i hope you've read in the markings schemes that A* is not available at the level of a single paper.
Hope it helps
THEIGBOY