well, if you full marked everything your standard score won't be 2.00 (it'll be higher)
grab a grade distribution and see for yourself.
NOTICE: first post edited, now added SS estimator.
Correct me if my calculations are wrong
Looking at 2007 Chemistry.
Full marks on first exam: standard score would be 1.77
Full marks on SACs: 1.49
Full marks on final exam: 1.87
I just subtracted the mean from the maximum score and then divided it by the standard deviation to find how many standard deviations from the mean the 100% was.
Based on that it is impossible to get standard score above 2 in 2007 Chemistry
btw, the calculator by grades is really quite good, at least in halting the flow of posts in the study score estimations thread
actually, no.
the figures VCAA give are truncated normal distributions, i.e. conditional probability need to be used. [there is a minimum and maximum]
hence, you need to
1) find the area from 0 marks to x marks
2) divide by the total area (from 0 marks to full marks)
3) multiply by the area from 0 to 50 (mean = 30, sd = 7)
4) add the tail from -infty to 0 (mean = 30, sd = 7)
5) invNorm (mean = 0, sd = 1)
that gives the standardised score for each GA
spreadsheet updated. I made an error in a formula (put - instead of +
)
please download again