The correct answer is that they 'are not valid'. If the experiment is biased, it entails that it is not objective. For a experiment, and its results, to be valid, it had to be carried out objectively and taking into account all factors.
It is possible that the results disprove a hypothesis, but to be certain it is necessary to see which was the original objective of the study, as it might also prove to some extent a hypothesis, which is probably also biased.
The proscenium stage is defined by its sharp separation of the action of the play from the audience (usually by the frame), while the thrust stage pushes the action of a play into the audience.
