The paper "Turning to Learn: Screen Orientation and Reasoning from Small Devices" describes a study that
investigated whether cell phones with small screens are useful for gathering information. The researchers wondered if the ability to reason using information read on a small screen was affected by the screen orientation. The researchers assigned 33 undergraduate students who were enrolled in a psychology course at a large public university to one of two groups at random.
One group read material that was displayed on a small screen in portrait orientation, and the other group read
material on the same size screen but turned to display the information in landscape orientation
The researchers found that performance on a reasoning test based on the displayed material was better for the group
that read material in the landscape orientation.
Is the study described above an observational study or an experiment?
(a) an observational study
(b) an experiment