While a Mod gets a coffee and some breakfast and moves this over to
Essex - Redbridge, l'll have a go at answering your question
However many questions there were on the papers, for the purposes of ranking the candidates, the raw scores are turned into standardised scores. This calculation involves the mean raw score and the standard deviation from the mean and will also compare those with similar dates of birth with each other, rather than with the whole cohort, then the resulting standardised score will be ranked., if the mean raw score etc for those of their sub-divisions of the age range are different.
You can see how the CSSE standardised scores are calculated in
Blitz's 'Collated Scores' thread over on the 'Essex' section of the Forum - not the same exam, obviously, but the general principle is the same and whereas the CSSE office has been providing the mean and sd each year for several years now, you won't get the same info from CEM.
With regard to age standardisation (which your exam supplier, CEM, definitely applies, but the CSSE up to now hasn't), this means that candidates with the same raw score but different months of birth may end up with different standardised scores, if the mean raw score etc for those of their sub-divisions of the age range are different.
The range of
standardised scores usually falls between a minimum of about 69 and a maximum of about 140, but it does depend on the distribution of the say scores around the mean.
Standardised scores, btw, are not 'out of' the maximum standardised score obtained from a given set of data (so if the maximum was, say, 140, an individual standardised score of 105 is not '75%', nor does it say anything at all about the number of questions on the paper that the candidate answered correctly).
Hope the helps a bit