Researchers tested out a breathing cushion students could use to relieve anxiety before an exam. Students in one group held the objecta plush, baby-blue cushion the size of a throw pillow that automatically inflates and deflates, mimicking inhaling and exhalingfor eight minutes before their exam. Another group did a guided breathing meditation instead, while another group didn't anything special. In the end, holding the plush object reduced anxiety as much as doing the meditation.

1. Based on the description, was the use of a breathing cushion measured or manipulated?
2. Based on the description, was exam anxiety measured or manipulated?
3. Is the study an experiment or a non-experiment?