This work performs an experimental study on the legibility of paths executed by a manipulation arm available on a Baxter robot. In this context, legibility is defined as the ability of people to effectively predict the target of the arm's motion. Paths that are legible can improve the collaboration of robots with humans since they allow people to intuitively understand the robot's intentions. Each experimental trial in this study reproduces manipulator motions to one of many targets in front of the robot. An appropriate experimental setup was developed in order to collect the responses of people in terms of the perceived robot's target during the execution of a trajectory by Baxter. The objective of the experimental setup was to minimize the cognitive load of the human subjects during the collection of data. The extensive experimental data provide insights into the features of motion that make certain paths more legible for humans than other paths. For instance, motions where the end-effector is oriented towards the intended target appear to be better in terms of legibility than alternatives.