Final answer:
Without the actual and estimated times, we cannot calculate the percentage by which physical therapists overestimated patient therapy time.
Step-by-step explanation:
The question provided does not include enough information to determine by what percent physical therapists overestimated the time they believed patients spent in therapy. To calculate a percentage of overestimation, one would need the actual time spent by patients in therapy and the time therapists believed patients spent. The calculation would then involve finding the difference between the estimated time and the actual time, dividing by the actual time, and then multiplying by 100 to get a percentage. Without specific numbers, this calculation cannot be completed.