Pretty good but all the information seems pushed together. Try making a graph with these number based on gold saved from most efficient to least efficient and it will be much more informative. You may also want to include that when buying something with Critical Chance, Attack Speed or Attack Damage you are increasing the effectiveness of that lifesteal.
You also need a baseline for the attack damage you are using the lifesteal with. This will allow you to show how much extra health per hit you are gaining when you include the AD, AS, and Crit.
Overall a decent study but not very detailed.