To OP,
If you score consistently in the mid-range ~50 percentiles on medentry, it's safe to add up to about 20 percentiles to the actual umat. Obviously you'd add less to your medentry percentiles if they are higher to begin with (which they are) as it gets progressively harder to increase percentiles in the upper range.
Ah okay. Are MedEntry exams actually harder than the real UMAT?
(Image removed from quote.)
Also, for that graph, what does UMAT3 Score (x-axis) refer to? The percentage of questions that you got correct in S3?
That is the raw score. It's an arbitrary number based on ACER's secretive methods and weightings, so no it is not an indicator of number or percentage of questions you answered correctly.
But I guess it can be in a way because if you assume that ACER's techniques don't radically alter the raw marks (as in number of questions correct), it kind of makes sense as a vague indicator of percentage of questions right. Randomly filling in every question would get you around 20% right on average which according to the graph is 0th percentile. Obviously students with their mental input will increase this. It maxes out at around 85% for 100th percentile (there may be some who get 100% right but remember out of 10000+ test takers, there are ~100 who get this percentile) which is fairly reasonable given the difficulty of the test.