Without specific data or results provided for each student, it's difficult to determine which student most likely had an error in their results. Typically, any of the following factors could indicate an error: significantly different times for the same ball, consistently longer or shorter times for all trials, or values that deviate greatly from expected results based on the laws of physics.
If you have any specific recorded times or patterns of results from Ziva, Jade, Owen, and Eduardo, please share those details, and I can help analyze who may have made an error in their investigation.