Hey tdotodot.
To answer this you need to have a distribution of marks. Do you want to assume that they are uniformly distributed from 0 to 40 (discrete uniform that is)?
I'm doing exam review and am having trouble with this. Can someone please help explain it to me?
This is one of the questions:
Scores on a Test are worth 40 marks.
a) If a student scores at the 80th percentile, what is the students raw score?
b) In which percentile are the students who scored 30/40?
c) If a student scores in the 70th percentile, what did they get on the test?
One reason I ask is that typically marks have more of a Normal distribution or a skewed distribution.
However if its uniform between a and b (whole numbers only and both inclusive) then the percentile score in percent for an observation x is p(x) = (x-a)/[b-a] * 100% where x lies in the interval of whole numbers [a,b]