After the final trial, we had the closest estimate out of the class, with an error of only 1%. This can be accounted for by outside forces, as the equations we used assumed that the circle made by spinning the string around was perfectly horizontal. We were unable to achieve this due to other forces such as wind resistance and because humans are not machines and can't create an exactly consistent motion throughout the duration of each trial.
Trials before the final test showed that our methods were consistent and our estimations were pretty accurate, so we know that the accuracy in the final test was not just luck, and our experiment was successful. We were able to apply the things we had learned about the physics of centripetal motion to a real life situation, and even derived a new equation to make our testing process easier and more accurate by quantifying by time for 30 revolutions rather than by velocity. One thing that would improve on our method would be if we could find a radius that would be suitable to use for every mass, rather than two radiuses for two different ranges. This would require some creative problem solving, as using two radiuses was our solution to the fact that we couldn't count the number of revolutions at a higher mass because our radius was too small and the weight was moving so fast. One possible solution would be to use a heavier weight, but this would cause the circle to become conical at lower masses.