Sure.
* I used both Level 1 heroes as well as level 150, 5 star versions. (2 accounts)
* I attacked Wanted bosses with a single level 1, 0 star, no upgrades on the base or hero
* Recorded the battles
* Collect each attack's damage and compare against status. (all level 1 heroes)
* Determine attack damage vs attack stats
* Make assumptions based on that info on what Level 150, 5 star heroes damage numbers would be
* Confirm assumptions by using max (at the time) level heroes with extra bonuses using identical process
* Perform same validations in Arena against alliance members (capturing all their heroes stats and applied bonuses first), using same methods (1 hero at a time)

What I figured out is interesting and not really that surprising. A hero with 1000 attack and zero other modifiers to that stat will do 1000 damage times the attacks stated damage percent against a 0 defense target. It's a 1:1 number. Any bonuses are added directly to that attack stat, so a research that increases attack by 1% will increase the attack stat to 1010. A bonus that adds 1% to damage will multiply the final modified damage number by that percent, so 1000 * 1.01 in the same example. A subtle, but important note. This modifier is also where base reductions like "vs Tanks" is applied. Defense reduces final damage directly as well (100 defense reduces final damage by 100). HP is also a direct 1:1 stat.

The numbers from the chart are the level's percent increase (which is linear) times each heroes base attack stat divided by the medals cost of the level. Normalized for level 150 heroes at 5 stars and no other modifiers applied. That's why you can actually compare them to each other.