Calculate Average of Top 5% of Biology Test Scores

[kankerfist]

I have some statistics on a test from my biology class and I was wondering if there is enough information provided by the stats to be able to calculate the average of the top 5% of scores. I have used a graph in mathematica to get a pretty good idea of what the top 5% average is, but I was wondering if anybody had any ideas on figuring this out. I've attached a jpg of the stats. Thanks a lot

 

[HallsofIvy]

According to your graph you have 250 scores so the top "5%" would be the top 12.5 scores. The only information shown is that 5 are between 90 and 100 (actually, it also says "highest grade 90" so presumably all 5 of those are 90) and 44 are between 80 and 90. Obviously, then, the top 12 are between 80 and 90, probably averaging close to 90, but without more precise information nothing more can be said.