How does the amount of water displaced depend upon the mass

Question

Described buoyancy experiment:

Analysis:

1. Find the volume of water displaced. The volume is given by: Where V is the volume, π is 3.14, r is the radius, and h is the increase in water level.
2. Find the mass of the ice. To do this, note that you just found the volume of the water displaced. The mass of this volume of water is equal to the mass of the ice. This mass can be found by: Where m is mass, ρ is the density of water (1 gm/cm3), and V is the volume of water displaced.

Concluding Questions:

1. How does the amount of water displaced depend upon the mass of the ice?
2. Most ice has some air bubbles in it. What effect does this have on the mass of the ice?  What effect does this have on the amount of water displaced?  Is this a concern, or will your measured mass still be correct if air bubbles are present?
3. What are some errors in this experiment?