A factory was trying out a new process for producing one of its products, with the goal of reducing productioncosts. A trial production run using the new process showed a 15 percent reduction in costs compared with pastperformance using the standard process. The production managers therefore concluded that the new processdid produce a cost savings.

Which of the following, if true, casts most doubt on the production manager's conclusion?

【选项】While the trial was being conducted, production costs at the factory for a similar product, produced without benefit of the new process, also showed a 15 percent reduction.